Russia launched airstrikes in Syria on Wednesday in the Kremlin's biggest Middle East intervention in decades, but Moscow's assertion that it had hit Islamic State was immediately disputed by the United States and rebels on the ground.
The airstrikes plunged the four-year-old civil war in Syria into a volatile new phase as President Vladimir Putin moved forcefully to assert Russian influence in the unstable region. The attacks also raised the dangerous specter of Washington and Moscow running airstrikes concurrently and in the same region, but without coordination.
U.S. Defense Secretary Ash Carter said he had directed U.S. military officials to meet with their Russian counterparts "as soon as possible" to discuss ways to make sure they do not come into conflict.