On 30 September 2015, following a formal request by the Syrian Government for military help against rebel and jihadist groups, Russia intervened militarily in theSyrian Civil War Actions consisted of air strikes primarily in north-western Syria against militant groups opposed to the Syrian government, including al-Nusra Front (al-Qaeda in the Levant), the Islamic State and the Army of Conquest.The Russian Air Force had significant ground support from the Syrian military,Iranian Revolutionary Guards, and allied militias. Prior to these operations, Russian involvement in the Syrian Civil War had mainly consisted of supplying the Syrian Army. Russian officials have acknowledged their objective is to help the Syrian government retake territory from various opposition groups, including groups backed and armed by the United States. The situation as it developed in October 2015 was widely assessed to be a proxy war between the United States and Russia

Background and preparation phase

The Syrian Civil War has been waged since 2011 between multiple opposition (anti-government) groupings and the government as well as their local and foreign support bases. Since 2014, a significant part of Syria′s territory had been claimed by the Islamic State, an entity internationally recognised as terrorist. In the north-west of the country, the main opposition faction is the al-Qaeda-affiliated al-Nusra Front allied with numerous other smaller Islamist groups, some of which operate under the umbrella of the Free Syrian Army (FSA) supported and armed by the U.S. and its regional allies. Since September 2014, the U.S.-led coalition had conducted air strikes in Syria against ISIL, which was widely seen as unsuccessful in achieving their ostensible goals.

According to Russian and Syrian officials, in July 2015 the Syrian President Bashar al-Assad made a formal request to Russia for airstrikes combatting international terrorism, while laying out Syria’s military problems. According to media reports with reference to anonymous sources, after a series of major setbacks suffered by the Syrian government forces in the first half of 2015, a political agreement was reached between Russia and Syria to intensify the Russian involvement; Qasem Soleimani, commander of the Iran′s Quds Force visited Moscow in July to work out the details of the joint campaign (Soleimani′s visit was denied by Russian officials).

In August 2015 Russia began to send Russian-operated warplanes, T-90 tanks and artillery, as well as combat troops to an airbase near the port city of Latakia in Syria. In September 2015, Russia′s warships of the Black Sea Fleet reached the area of eastern Mediterranean.

At the end of September, a joint information centre in Baghdad was set up by Iran, Iraq, Russia and Syria to coordinate their operations against ISIL (in the newsmedia the centre is also referred to as "Joint Operations Room in Baghdad known as the 4 + 1" implying the Lebanese Shia militia Hezbollah, in addition to the 4 states). According to Russian foreign minister Sergey Lavrov′s statement made in mid-October 2015, prior to the start of its operations in Syria, Russia invited the U.S. to join the Baghdad-based information center but received what he called an "unconstructive" response. According toAlexander Yakovenko, Ambassador of Russia to the United Kingdom, the Russian government received a similar rebuttal from the UK government.

On 30 September 2015, the upper house of the Russian Federal Assembly, the Federation Council, granted the request by Russian President Vladimir Putin to deploy the Russian Air Force in Syria. On the same day, the Russian representative to the joint information centre arrived at the U.S. Embassy in Baghdad and requested that any U.S. forces in the targeted area in Syria leave immediately. An hour later, the Russian aircraft based in the government-held territory began conducting airstrikes ostensibly against ISIL and other rebel targets.

Prior to the start of the Russian operation in Syria as well as afterwards, Russian analysts believed that Russia′s military build-up in Syria was aimed inter aliaat ending the de facto political and diplomatic isolation that the West had imposed on Putin in connection with the situation in Ukraine.

Operations by Russian military

September—mid-November 2015

The first series of air strikes took place on 30 September 2015 in areas around the cities of Homs and Hama, targeting the mainstream opposition. Russian warplanes attacked rebel positions "in al-Rastan, Talbiseh and Zafaraniya in Homs province; Al-Tilol al-Hmer in Quneitra province; Aydoun, a village on the outskirts of the town of Salamiya; Deer Foul, between Hama and Homs; and the outskirts of Salmiya".In total, 20 flights were made. Most of the initial airstrikes targeted positions of the Chechen fighters, Islamic Front's Jaysh al-Islam (Army of Islam), and Free Syrian Army.

According to Hezbollah media outlet Al Mayadeen, the Saudi/Turkish-backed Army of Conquest around Jisr ash-Shugour was bombed on 1 October by Russian planes; at least 30 air strikes were carried out. Another series of Russian airstrikes carried out that same day hit ISIL positions in Raqqa governorate.

In the morning of 2 October, the Russian air force launched four airstrikes on ISIL in the ancient Syriac city of Al-Qaryatayn, and the T4-Palmyra highway,Homs province. An ISIL command and control center was destroyed in a single airstrike in Al-Qaryatayn, while an ISIL convoy on their way to the Teefor-Palmyra highway was attacked. Following the airstrikes, the Syrian Army and National Defence Forces pushed ISIL out of the town of Mheen towards Al-Qaryatayn after a two-hour engagement that killed 18 militants and destroyed two technicals mounted withZU-23-2s. Syrian forces then launched a counter-attack south-west of Al-Qaryatayn to recover the main road.

In the same day, the Russian Air Force began bombingAl-Nusra Front positions in al-Rastan and Talbiseh in the Homs province. Later, they proceeded with bombing Al-Nusra in Kafr Zita, Al-Ghaab Plains, Kafr Nabl, Kafr Sijnah, and Al-Rakaya in the Hama province. The Syrian Air Force and the Russian Air Force jointly bombed Al-Nusra in Jisr al-Shughur. At night, the Russian Air Force targeted ISIL with 11 airstrikes over Al-Raqqah while targeting electrical grids outside it, two airstrikes over Shadadi-Hasakah highway, and three airstrikes in Al-Mayadeen, Deir ez-Zor province. The primary ISIL military base inTabaqa Military Airport was also attacked, with the barracks being destroyed in two airstrikes. Near the Military Airport, an ISIL weapons supply depot in Al-'Ajrawi Farms was also bombed. At the same time, the ISIL primary headquarters in Tabaqa National Hospital was heavily damaged in a Russian airstrike. In Al-Hasakah province, the Russian Air Force targeted ISIL in Al-Shadadi and Al-Houl, while the Syrian Air Force attacked an ISIL convoy along the Deir ez-Zor-Hasakah highway.

On 3 October, reports indicated that Hezbollah and Iranian fighters were preparing major ground offensives to be coordinated with Russian airstrikes. According to CNN, the Russian defense ministry said its soldiers bombed nine ISIL positions near the group's de facto capital in Raqqa. At least 11 were killed in an alleged double strike by Russia in Syria's Idlib province, according to opposition groups.During the day, the Russian Air Force made four airstrikes over Al-Nusra controlled Jisr al-Shughur, and additional ones in Jabal Al-Zawiya, and Jabal al-Akrad. One of the targets was an Al-Nusra reinforcement convoy heading from Jisr al-Shughur to the northeast countryside of Latakia province.

On the morning of 7 October 2015, according to the Russian officials, four warships from the Russian Navy's Caspian Flotilla launched 263 M-14T from Kalibr-NK system cruise missiles that hit 11 targets within Syrian territory. The missiles passed through Iranian and Iraqi airspace in order to reach their targets at a distance of well over about 1,500 kilometers (930 miles). The same day, Syrian ground forces were reported to carry out an offensive under Russian air cover. According to CNN citing unnamed U.S. military and intelligence officials, 4 of 26 cruise missiles on 8 October crashed in Iran, well before reaching their targets in Syria. Russia claimed all of its missiles hit their targets.Iran also denied any missile crash on its territory. Iranian defence ministry rejected any reports alleging that four of the 26 cruise missiles crashed in Iran saying the CNN reports are part of the West's "psychological warfare".

On 8 October 2015, the number of air raids increased significantly up to over 60 sorties a day, a tempo maintained for the next 2 days.The Russian defense ministry announced on 9 October that up to sixty ISIL targets were hit in the past 24 hours, supposedly killing 300 militants in the most intense strikes so far. One of the raids targeted a Liwa al-Haqq base in the Al-Raqqah Governorate using KAB-500KR precision-guided bombs, in which two senior ISIL commanders and up to 200 militants were killed, despite the lack of connection between Liwa al-Haqq and ISIL. Another assault destroyed a former prison near Aleppo that was used by ISIL as a base and munitions depot, also killing scores of militants. Rebel training sites in the Latakia and Idlib provinces were allegedly hit as well. Meanwhile, ISIL militants made advances in the Aleppo area on 9 October, seizing several villages, including Tal Qrah, Tal Sousin, and Kfar Qares, in what theAssociated Press called a "lightning attack". The attacks were unencumbered by either Russian or U.S.-led coalition airstrikes. The ISIL advance came at the expense of rebel groups also targeted by Russian and Syrian forces.

In mid-October 2015, a joint Russian-Syrian-Iranian-Hezbollah offensive targeting rebels in Aleppo went ahead.

According to the data released by the Russian Defence Ministry, within the period from 30 September till 22 October 2015, the Russian aircraft carried out 934 sorties from the Hmeymim air base and destroyed 819 targets. By 17 November 2015, according to the Russian Defence ministry, Russia′s air force had flown the total of 2,300 missions over Syria.

Since mid-November 2015

On 17 November 2015, in the wake of the Russian jet crash over Sinai and the Paris attacks, according to the Russian defence minister′s public report to the president of Russia Vladimir Putin, Russia employed the Russia-based Tu-160, Tu-95MSM, and Tu-22M3 long range strategic bombers firing air-launched cruise missiles to hit what he claimed were the IS targets in Raqqa, Deir ez-Zor as well as targets in the provinces of Aleppo and Idlib. The Russian minister of defence said that, pursuant to Putin′s orders, the Russian aviation grouping that at the time comprised more than 50 aircraft was intensifying their campaign. Besides, Putin said he had issued orders for the Moskva cruiser that had been in eastern Mediterranean since the start of the Russian operations to "work as with an ally", with the French naval group led by flagship Charles De Gaulle that had been on its way to eastern Mediterranean since early November.The following day, according to the Russian Defence ministry, strikes by long-range bombers firing cruise missiles in the same areas in Syria continued. The mass cruise missile strikes carried out against ISIS in Deir Ezzor province on 20 November resulted in the death of more than 600 militants according to the ministry. A Russian Sukhoi Su-24 strike aircraft was purportedly shot down by a Turkish Air Force F-16 on 24 November 2015.

On 24 November 2015, a Russian warplane was shot down in the Syrian-Turkey border area. Turkey claims the plane violated Turkish airspace, a claim Russia denies. Early reports from multiple Russian news agencies indicated that the plane had been downed by a ground-based strike from Syrian rebels, but Russian officials later confirmed the Turkish reports that the plane had been downed by Turkish fighter jets. According to Turkish officials, the Russian jet, an SU-24, was shot down by two Turkish F-16 jets after multiple requests (10 requests in a five minute span) for the Russian jet to change its course

Weapons and munitions employed

Russian forces in Syria were reported to have used a mix of precision-guided munitions and unguided weapons. The October airstrikes were Russia's first operational use of precision-guided munitions, whose development in Russia lagged behind other nations due to economic instability in the 1990s. The majority of weapons employed, however, were unguided. Russia also utilized cruise missiles launched from corvettes and a frigate.Russian artillery has also been used in the form of howitzers and multiple rocket launchers.

"Exploding suicide drones" have allegedly been deployed by Iran and Russia, according to some American media sources.Overall, the air campaign is estimated to cost between $2.3 and $4 million a day. Additionally, the 3M-14T cruise missiles that Russia has used by the dozen cost roughly $1.2 million per unit.