The US, France and Britain have been stepping up military deployment around Syria, ahead of a US congress vote on a military strike.

By the end of August, the US had five warships in the eastern Mediterranean, capable of launching Tomahawk cruise missiles at land targets. Two US aircraft carriers are currently in the Red Sea and the Persian Gulf.

Meanwhile, the French aircraft carrier Charles de Gaulle is on standby in the southeast city of Toulon in the Mediterranean. France also has Rafele and Mirage fighter jets deployed in the United Arab Emirates.

The British Royal Navy has at least one submarine in the area, and The Royal Air Force has recently sent six Typhoon fighter jets to an airbase in Cyprus. But the British defense ministry has called it a prudent and precautionary measure, not aimed at engaging in military action against Syria.