Seven US military aircraft have conducted reconnaissance missions near the coast of Syria, where Russia's Hmeymim airbase and Tartus naval base are located, Moscow's military flight monitoring centre tweeted on Friday.
Six US 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, Xinhua news agency reported.
The escalation of tension around Syria comes against the backdrop of reports on the latest chemical weapons use in Eastern Ghouta's Douma which killed 74 people including children.
US 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.
--IANS
and/ksk