U.S. Secretary of State John Kerry spoke by telephone on Tuesday with his Russian counterpart, Foreign Minister Sergei Lavrov, and the conflict in Syria was on Kerry's agenda for the discussions, the U.S. State Department said.

State Department spokesman John Kirby did not immediately offer details of the call between Kerry and Lavrov, but Russia's Foreign Ministry said Lavrov had stressed the need to create a united front to battle terrorist groups in Syria.

U.S. officials have indicated that Russia is increasing its military presence in Syria and have expressed concern about whether Moscow is boosting support for Syrian President Bashar Assad.

The Russian Foreign Ministry added in a statement on its website that Kerry and Lavrov also discussed the Ukraine crisis and steps to ease tension on the Korean Peninsula, without providing further detail.

(Reporting by Arshad Mohammed and Alexander Winning; writing by David Alexander)