Players in the battle for Syria

Syria's intractable civil war became even more complicated last week when Russia attacked rebel positions in support of the embattled government of President Bashar Assad. The main players in the multisided war of attrition:

United States: The U.S. is leading an international coalition that has conducted hundreds of airstrikes in Syria and Iraq against the Islamic State in Iraq and the Levant since last year. The U.S. also has provided limited support to some of the moderate rebel factions trying to overthrow Assad. A separate Pentagon program to train and equip a Syrian proxy force to fight ISIL has been beset with problems.

Russia: Russia says its attacks in support of Assad's government target positions held by ISIL. The Kremlin argues that ISIL won't be defeated without shoring up Assad.

Iran: Iran has been Assad's most important backer, providing funding, weapons and other critical aid.

Saudi Arabia: Frustrated that the U.S. has not acted more forcefully against Assad, Saudi Arabia and other Sunni Arab states are bankrolling rebel groups fighting Syria, which they view as a proxy of Shiite-led Iran. The kingdom has provided warplanes to the U.S.-led coalition fighting ISIL.

Qatar: Qatar provides funding and military aid to a number of Syrian rebel groups. But it has been at odds with Saudi Arabia over which groups to support.

Turkey: Turkey has been a reluctant ally in the U.S.-led campaign against ISIL. Until July, it refused to allow coalition warplanes to use Turkish air bases to launch attacks in Syria. Turkish jets joined in the bombing campaign in August.

France: It was the first European country to launch strikes against ISIL and in September carried out strikes in Syria.

Britain: The British Parliament voted against taking military action in Syria and the country has directed most of its efforts on behalf of the coalition targeting ISIL in Iraq. In August, however, Britain carried out a drone strike in Syria.

Los Angeles Times