MOSCOW, April 13 (Xinhua) -- Seven U.S. military aircraft have conducted reconnaissance missions near the coast of , where 's Hmeymim airbase and Tartus naval base are located, Russian military flight monitoring center said Friday on its Twitter account.

Six U.S. Navy P-8A Poseidon patrol aircraft departed from an airbase on the Italian island of Sicilia, and an EP-3E Aries II reconnaissance aircraft flew from the base on the Greek island of Crete, said the center.

The escalation of tension around Syria comes against the backdrop of reports on the latest chemical weapons use in Syria's Douma.

U.S. President Donald Trump had earlier threatened military action against the Syrian government which he blamed for the alleged chemical attack. The Syrian government has denied such an accusation.