Russian Foreign Minister Sergei Lavrov has discussed the Syrian conflict with U.S. Secretary of State John Kerry amid concerns in Washington about a Russian military buildup in the war-torn country.
The Russian Foreign Ministry said the two discussed via telephone on September 9 "the problems of regulating the conflict in Syria" as well as "aspects of Russian-American bilateral relations."
It added that "Lavrov once again highlighted the significance of a consolidated response to terrorist groupings that have seized a sizable part" of Syria and are threatening "international security."
U.S. officials said on September 8 that three Russian military transport planes had landed in Syria in recent days.
U.S. military officials have also said new housing units had been set up at the airport in the port city of Latakia, the hometown of Syrian President Bashar al-Assad.
Syrian officials deny that Russians forces have taken part in combat, but Moscow and Damascus have said Russian military advisers are on the ground in Syria.
Russia's only naval base in the Mediterranean Sea is on the Syrian coast at Tartus.