Hundreds of Iranian troops have arrived in Syria to join a major ground offensive in support of President Bashar al-Assad’s government, Lebanese sources said on Thursday, a sign the civil war is turning still more regional and global in scope.

Russian warplanes, in a second day of strikes, bombed a camp run by rebels trained by the CIA, the group’s commander said, putting Moscow and Washington on opposing sides in a Middle East conflict for the first time since the Cold War.

Speaking by video link for an hour, U.S. and Russian military officials discussed ways to ensure their warplanes do not come into conflict as they carry out separate air campaigns over Syria, White House spokesman Josh Earnest told reporters. He said it was the first in a series of conversations. […]