America's Western allies are gearing up their troops for possible deployment to the Gulf in the event of a war with Iraq. The UK is expected to announce on Tuesday a decision to mobilise thousands of troops and send a helicopter assault ship to the region later this month. In France, President Jacques Chirac said soldiers needed to be prepared in case new areas of engagement opened up - his clearest reference yet to the prospect of French involvement in any military action in Iraq.

It comes amid a massive build-up of US forces in the Gulf region, as United Nations weapons inspectors continue to search Iraq for the weapons of mass destruction.

In a message to France's armed forces, Mr Chirac said that "alas, other [theatres] could open up", in addition to the Ivory Coast, where a French peacekeeping force is serving.

"Particularly, we have to be attentive to the way in which United Nations Security Council resolution 1441 is applied by Iraq," he said.

The BBC's Paris correspondent, Jon Sopel, says Mr Chirac is slowly trying to massage public opinion, readying it in case military action does take place and French soldiers are called to serve alongside American troops.

France has long opposed the prospect of unilateral military action by America against Iraq, insisting any resort to force must be approved by the UN first.

Call up

Later on Tuesday, the UK Defence Secretary Geoff Hoon is expected to give more details of Britain's military preparations for a potential war against Iraq.

His announcement is expected to include the call-up of about 7,000 specialist reservists and details about the deployment of a Royal Navy task force to the Gulf.

The task force, led by the aircraft carrier HMS Ark Royal, is due to set sail in mid-January.

So far, few of America's other allies have made any definite practical commitments to joining possible operations against Iraq.

Other light British forces, including paratroopers, are also reportedly stepping up their training.

US deployment

Thousands of American soldiers are being deployed to the region this week, joining the 50,000 already there.

The White House has also ordered the aircraft carrier USS Abraham Lincoln to abandon its voyage home and return to Australia, fuelling speculation that plans are being made to use the vessel in a campaign.

The giant US Navy hospital ship, USS Comfort, also left her home port of Baltimore on Monday and is thought to be heading to Diego Garcia in the Indian Ocean. At least 10,000 US reservists have been told to prepare for possible overseas deployment as early as this week to support the build-up. The US Army has also started deploying more than 11,000 soldiers from the 3rd Infantry Division in Fort Benning and Fort Stewart in Georgia - specialists in desert warfare.

Correspondents say that many of these troops are veterans from Desert Storm, the US-led military operation to remove the Iraqi army from Kuwait over 10 years ago.

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At least 50,000 US troops are already in the region