Syrian rebels in training

The United States has carried out a fresh delivery of ammunition to fighters from the Syrian Arab Coalition battling Islamic State in northern Syria, pushing ahead with a strategy that initially unnerved ally Turkey, a U.S. official told Reuters on Sunday.

The delivery of ammunition represented only the second time the United States has moved to arm the Syrian Arab Coalition, a collection of about 10-12 groups numbering about 5,000 fighters. They are working with Kurds and others to claw back land from Islamic State.

In a shift in approach, the latest U.S. resupply operation was completed on Saturday by delivering the weaponry by land, the U.S. official said, speaking on condition of anonymity.

Obama and Putin, with Susan Rice in Turkey

In a related development,  U.S. President Barack Obama vowed on Sunday to step up efforts to eliminate Islamic State and prevent more attacks like those in Paris, while urging Russia’s Vladimir Putin to focus on combating the jihadist group in Syria.

A White House official said Obama and Putin agreed in a 35-minute meeting on the sidelines of a G20 summit in Turkey on the need for a political transition in Syria, saying events in Paris had made it all the more urgent.

“The skies have been darkened by the horrific attacks that took place in Paris just a day and a half ago,” Obama said.

“We will redouble our efforts, working with other members of the coalition, to bring about a peaceful transition in Syria and to eliminate Daesh as a force that can create so much pain and suffering for people in Paris, in Ankara, and in other parts of the globe,” he said, using the Arabic acronym for Islamic State.

U.S.-led efforts to combat Islamic State were complicated when Russia joined the conflict a month and a half ago, targeting what the West says are mainly areas where foreign-backed fighters are battling Assad, Moscow’s ally, rather than Islamic State.