section_path: History/Obama administration (2009–2017)/Russian military intervention in the Syrian Civil War (from September 30, 2015)
section_name: Russian military intervention in the Syrian Civil War (from September 30, 2015)
paragraph_text: Russian military intervention in the Syrian Civil War (from September 30, 2015)
  
  Shortly after the start of the Syrian Civil War in the spring of 2011, the U.S. imposed sanctions on Syria's government and urged President Bashar al-Assad to resign; meanwhile, Russia, a long-standing ally of Syria, continued and increased its support for the Syrian government against rebels backed up by the U.S. and its regional allies.
  
  On September 30, 2015, Russia began the air campaign in Syria on the side of the Syrian government headed by President Bashar al-Assad of Syria. According to Russian foreign minister Sergey Lavrov 's statement made in mid-October 2015, Russia had invited the U.S. to join the Baghdad-based information center set up by Iran, Iraq, Syria and Russia to coordinate their military efforts, but received what he called an "unconstructive" response; Putin's proposal that the U.S. receive a high-level Russian delegation and that a U.S. delegation arrive in Moscow to discuss co-operation in Syria was likewise declined by the U.S.
  
  In early October 2015, U.S. president Obama called the way Russia was conducting its military campaign in Syria a "recipe for disaster"; top U.S. military officials ruled out military cooperation with Russia in Syria. Secretary of Defense Ashton Carter and other senior U.S. officials said Russia's campaign was primarily aimed at propping up Assad, whom U.S. president Barack Obama had repeatedly called upon to leave power.
  
  Three weeks into the Russian campaign in Syria, on October 20, 2015, Russian president Vladimir Putin met Bashar al-Assad in Moscow to discuss their joint military campaign and a future political settlement in Syria, according to the Kremlin report of the event. The meeting provoked a sharp condemnation from the White House.
  
  While one of the original aims of the Russian leadership may have been to normalize relations with the U.S. and the West at large, the resultant situation in Syria was said in October 2015 to be a proxy war between Russia and the U.S. The two rounds of the Syria peace talks held in Vienna in October and November 2015, with Iran participating for the first time, highlighted yet again the deep disagreement over the Syrian settlement between the U.S. and Russia, primarily on the issue of Bashar al-Assad 's political future. The talks in Vienna were followed by a bilateral meeting of Obama and Putin on the sidelines of the G-20 Summit in Turkey, during which a certain consensus between the two leaders on Syria was reported to have been reached.
  
  Bilateral negotiations over Syria were unilaterally suspended by the U.S. on October 3, 2016, which was presented as the U.S. government's reaction to a re-newed offensive on Aleppo by Syrian and Russian troops. On the same day Putin signed a decree that suspended the 2000 Plutonium Management and Disposition Agreement with the U.S. (the relevant law was signed on October 31, 2016), citing the failure by the U.S. to comply with the provisions thereof as well as the U.S.' unfriendly actions that posed a "threat to strategic stability."
  
  In mid-October 2016, Russia's U.N. ambassador Vitaly Churkin, referring to the international situation during the 1973 Arab–Israeli War, said that tensions with the U.S. are "probably the worst since 1973". After two rounds of fruitless talks on Syria in Lausanne and London, the foreign ministers of the U.S. and the UK said that additional sanctions against both Russia and Syria were imminent unless Russia and the "Assad regime" stopped their air campaign in Aleppo.