Rear admiral David Nichols, deputy commander of the air operation centre, told reporters US air operations would be shut down totally at Prince Sultan air base at Kharj, 80 kilometers (50 miles) south of the capital Riyadh, by the end of the summer.

"The move was by mutual agreement with the Saudis," he said.

Asked how many aircraft would remain at the base by the end of the summer, Air Force spokesman Major General Ronald Rand replied: "US airplanes zero".

"We already have switched" the air operations centre from Prince Sultan to Al-Udeid in Qatar, Nichols said.

"As of yesterday the ATO (Air Tasking Order) is being planned and executed out of Al-Udeid."

The US Air Force has been using the giant Al-Udeid facility to run air operations in Afghanistan and the Horn of Africa.

At the peak of operations during the Iraq war as many as 2,700 missions a day were handled by the headquarters in Saudi Arabia.

About 100 coalition aircraft were still at Prince Sultan base on Tuesday compared to a peak of 200.

All that will be left is "training, engagement and exercising", said Rand.

Nichols said Prince Sultan base would still be wired but computers and other equipment would largely be taken out. However, he added that it could easily be reinstalled.

The revelation of the long-awaited move in the aftermath of the September 11, 2001 suicide hijacking in the United States, in which 15 Saudis led by Osama bin Laden, played a leading role, came during a visit by Defence Secretary Donald Rumsfeld.

He flew into what had served as coalition air force headquarters during the Iraq war to meet troops at the base and Saudi leaders in the nearby capital.

The visit to a key Gulf ally came after Rumsfeld announced in Qatar on Monday that the United States would reduce its military forces in the Gulf now Iraq no longer poses a threat to the region.

Rumsfeld was set to have talks with Crown Prince Abdullah and Defence Minister Prince Sultan, officials said.

For the Iraq war, the United States had more than doubled its troops in the kingdom to 10,000, a majority of them stationed at Prince Sultan.

Some 5,000 US troops, mostly airmen, and around 40 US, British and French aircraft had been stationed at the air base since the end of the 1991 Gulf war, mainly to enforce a no-fly zone over southern Iraq.

SPACE.WIRE