By Peter Biles BBC correspondent in Doha

The United States has for the first time allowed journalists into one of its military bases in the tiny Gulf state of Qatar, where a secret training exercise is under way.

If we've got combat operations going on at the same time as strategic manoeuvres, then this place really gets to hopping Colonel Tom Bright

Hundreds of coalition forces are involved in the operation, code-named Internal Look.

Although the US military deny there's any connection to events in Iraq, the exercise is widely seen as a rehearsal for a possible war against Saddam Hussein's regime.

The exercise - the first of its kind outside the US - is about how to set up a mobile headquarters thousands of kilometres from home, in order for troops to be deployed more quickly.

Computer games

With its rows of drab warehouses, the al-Sayliyah base in Qatar is an unlikely venue for state-of-the-art computer-based war games.

	:	Military balance
Iraqi and US forces in the region

It looks like an extension of the nearby industrial estate on the outskirts of the Qatari capital, Doha.

There are no combat troops or military hardware here.

Instead, servicemen and women work feverishly at computer terminals.

This command, control and communications exercise was organised by US Central Command in Florida.

The staff involved - American, British and other nationalities - won't reveal the fictitious military scenarios they're being confronted with.

Officially, they say, the operation is nothing to do with the crisis in Iraq.

But it's no secret that in the event of a war, Qatar will be one of Washington's most important allies in the region.

Hero's welcome

In the nerve centre of the military base, Colonel Tom Bright, the chief of operations for US Central Command, says they are working around the clock.

"If we've got combat operations going on at the same time as strategic manoeuvres, then this place really gets to hopping," he says.

Rumsfeld got a warm welcome from US troops

Operation Internal Look will end next week, after which most of those taking part, will return home.

However, up to 5,000 American troops are based in Qatar, and many of them gave US Defence Secretary, Donald Rumsfeld, a hero's welcome when he arrived here at the end of a four nation tour of the Horn of Africa and the Gulf.

His visit was aimed at bolstering support for the war against terrorism.

On the stage in the main hall, Mr Rumsfeld was joined by America's top general, Tommy Franks, who is in charge of this week's military exercise in Qatar.

General Franks is expected to lead US forces in the event of a war with Iraq.

Captain Amy Souza from an air base in Georgia was among the US troops given a rare chance to quiz the Defence Secretary.

In reply to Captain Souza's question about whether Iraq was co-operating with the UN weapons inspectors, the Mr Rumsfeld said Iraq's huge declaration on its weapons programmes still needed detailed study.

"We're at an early stage," Mr Rumsfeld said.

"In a relatively short period of weeks, people will have had enough time to look at the document, think about it, analyse it, and then discuss it with other countries and come to some conclusions."