Russia appeared to seize the initiative in international efforts to end the conflict in Syria on Sunday as Washington scrambled to devise a new strategy for the war-ravaged country and France sent warplanes to bomb Islamic State targets.
As leaders gathered in New York at the United Nations General Assembly, U.S. Secretary of State John Kerry discussed Syria with Russian Foreign Minister Sergei Lavrov. He said that while it was vital to coordinate efforts against Islamic State militants this was not yet happening.
"I think we have concerns about how we are going to go forward," Kerry told reporters. U.S. officials said Kerry was working on a new political initiative in New York that would include Russia and key regional powers.
A senior State Department official told reporters: "It was a very thorough exchange of views on both the military and the political implications of Russia's increased engagement in Syria."
Kerry also discussed Syria with Iran's foreign minister during a meeting at the United Nations on Saturday.
It was announced in Baghdad that Russian military officials were working with counterparts from Iran, Syria and Iraq on intelligence and security cooperation to counter Islamic State, which has captured large areas of both Syria and Iraq.
The move was seen in the region as potentially giving Moscow more sway in the Middle East.
Russian President Vladimir Putin derided U.S. efforts to end the Syria war, which has driven a tide of refugees into neighbouring states and Europe.
He said Moscow, which this month sent tanks and warplanes to a Russian military base in Syria, was itself trying to create a "coordinated framework" to resolve the conflict.
"We would welcome a common platform for collective action against the terrorists," Putin said in an interview on Sunday on CBS's "60 Minutes."