In response to rapid territorial gains made by the Islamic State of Iraq and the Levant (ISIL, ISIS, IS, or Daesh, calling itself the Islamic State) militants during the first half of 2014, and the group's internationally condemned brutality, reported human rights abuses and the fear of further spillovers of the Syrian Civil War, many states began to intervene against ISIL in Syria and Iraq. Later, there were also minor interventions by some states against ISIL-affiliated groups in Nigeria and Libya.
ISIS continues to gain substantial ground in Syria, despite US intervention. When the Russian intervened Hundreds of cities, towns and villages in Syria were liberated from ISIS control raising questions that the US was not serious in fighting ISIS but the Syrian government. The US has a history of using terrorism to topple governments friendly to Russia.
In mid-June 2014, Iran, according to American and British information, started flying drones over Iraq, and, according to Reuters, Iranian soldiers were in Iraq fighting ISIL. Simultaneously, the United States ordered a small number of troops to Iraq and started flying manned aircraft over Iraq.
In July 2014, according to the International Institute for Strategic Studies, Iran sent Sukhoi Su-25 aircraft to Iraq, and Hezbollah purportedly sent trainers and advisers to Iraq to monitor ISIL's movements. In August 2014, the US and Iran separately began a campaign of airstrikes on ISIL targets in Iraq. Since then, fourteen countries in a US-led coalition have also executed airstrikes on ISIL in Iraq and in Syria.
In September 2015, Russian forces, at the request of the Syrian government, began hundreds of bombing raids against Syrian rebel groups, including ISIL (and the FSA).
In mid-2016, US-led coalition and Russian-led planning coordinated.