RAF jets have been sent to Cyprus, the Ministry of Defence confirmed - but they will not be used to bomb Syria.
The six Typhoon jets would be used protect UK interests and sovereign bases "at a time of heightened tension in the wider region", the MoD said.
They are being deployed to Akrotiri in Cyprus on Thursday as a "prudent and precautionary measure".
A spokesman said: "We can confirm that as part of ongoing contingency planning, six RAF Typhoon interceptor fast jets are deploying this morning to Akrotiri in Cyprus.
"This is purely a prudent and precautionary measure to ensure the protection of UK interests and the defence of our sovereign base areas at a time of heightened tension in the wider region.
"This is a movement of defensive assets operating in an air-to-air role only. They are not deploying to take part in any military action against Syria.
"The PM has made clear no decision has been taken on our response and the Government has said that there will be a Commons vote before direct military involvement."
The Typhoons have been deployed in a defensive counter air (DCA) role, the RAF said, and are fitted with advanced medium range air-to-air missiles (AMRAAM), advanced short range air-to-air missiles (ASRAAM), and a Mauser cannon for close combat.
The deployment comes after two Tristar air-to-air refuelling aircraft and one E3D Sentry airborne warning and control system (AWACS) command and control aircraft were sent to RAF Akrotiri in Cyprus on Tuesday, the RAF said.
Cyprus's sovereign base areas are said to provide a "strategic forward mounting base" in a region important to the UK's long-term national security interests.
There are around 2,500 military and UK civilian personnel serving on the bases, along with around 3,000 accompanying family members and dependants.
RAF Akrotiri is home to 84 Squadron search and rescue helicopters, and is also where troops returning from operations in Afghanistan spend several days on "decompression" before returning to the UK.
A further 270 UK personnel are based in Nicosia on peacekeeping duties as part of UN forces in Cyprus.
As a British Overseas Territory rather than part of the Republic of Cyprus, Britain does not need Cypriot agreement to deploy the Typhoons, but the RAF said it was keeping in close contact with the government.