The United States has moved an air operation center from Prince Sultan air base in Saudi Arabia to one in Qatar, officials said Tuesday. Vice Adm. Dave Nichols, a top official at the center, said operations were shifted Monday to Qatar's al-Udeid air base. Nichols and other officials said nearly all of the 4,500 Air Force personnel here will be gone by the end of the summer. Defense Secretary Donald H. Rumsfeld and Air Force officials here said the United States is refocusing its military relationship with Saudi Arabia to training Saudi forces rather than having large numbers of U.S. troops based here.

Rumsfeld spoke to troops in a hanger Tuesday morning after landing in the middle of a sandstorm after a flight from Qatar.

He thanked them for their efforts in overthrowing the regime of Saddam Hussein in Iraq .

Shift of the air operations center from Saudi Arabia to Qatar is the first major step in a series of likely shifts in the region.

Gen. Tommy Franks, who commanded the Iraq war from a base in Qatar, had signaled the move earlier, noting that both the Prince Sultan and al-Udeid bases have the high-tech equipment needed for American commanders to simultaneously keep track of hundreds of air missions over Iraq, Afghanistan and other countries in the region.

Saudi officials have been uneasy about the presence of U.S. troops in their country since the 1991 war with Iraq, as shown by their attempts to stifle news that American commanders were running the Iraq air war from the Prince Sultan base.

But U.S. officials say moving the air operations center should not be seen as evidence of a rift between the two nations.

Instead, they say, it's part of an inevitable repositioning of U.S. forces in the Persian Gulf region now that one of its main military threats - Saddam's regime - is gone.

Rumsfeld is touring the region this week to talk with allies before reaching final decisions. He met Monday with Qatar's leader, Sheik Hamad bin Khalifa Al Thani, who allowed the U.S. headquarters for the war to be built near here.

"Iraq was a threat in the region, and because that threat will be gone, we also will be able to rearrange our forces," Rumsfeld said after meeting with Thani and Australian Defense Minister Robert Hill.

The presence of thousands of American soldiers in Saudi Arabia, the land of Islam's two holiest shrines, has enraged some militant Muslims. It is among the reasons given by Osama bin Laden , the Saudi-born fugitive who heads the al-Qaida network, for his hatred of the United States.

Rumsfeld said Monday that the Bush administration has "a good and close relationship" with the Saudi government.

Tens of thousands of American service members were stationed in the region before the war with Iraq. Air Force and Navy aircraft patrolled no-fly zones over Iraq. Army soldiers and Marines held exercises in Kuwait as a warning to Saddam. Naval vessels patrolled the gulf, helping to look for ships violating the U.N. embargo against Iraq.

None of those jobs is needed now that Saddam is no longer in power. Once Iraq is stabilized, the number of U.S. troops in the region should drop, Rumsfeld said. He added he does not want to have permanent U.S. access to military bases inside Iraq.

The defense secretary also is using his trip to thank some of the American troops involved in the U.S.-led campaign to depose Saddam. Although Rumsfeld has insisted he is not on a "victory tour," he basked Monday in the American military success.

In a U.S. military warehouse at Camp As Sayliyah, Franks' headquarters for the three-week war, Rumsfeld told cheering troops their triumph will influence military spending and doctrine for decades.

The military, he said, used "an unprecedented combination of power, precision, speed, flexibility and, I would add, compassion."

"You protected our country from a gathering danger and liberated the Iraqi people," Rumsfeld said. Later, he added, "You liberated a country, but how you did it will help transform the way we defend our country in the 21st century."

Rumsfeld met with Hill, the Australian defense minister, at a luxury hotel at the edge of the Persian Gulf. After their meeting,

Hill said Australia, which contributed several thousand troops to the war effort, was looking for ways to help during the postwar phase in Iraq. Most of that help would come in "niche operations" such as helping with the hunt for chemical and biological weapons, he said.

Fifty Australian air traffic controllers are headed to Baghdad International Airport to help coordinate humanitarian aid flights, Hill said.

PHOTO CAPTION

U.S. Secretary of Defense Donald Rumsfeld speaks to coalition troops Monday, April 28, 2003 during his visit to U.S. Central Command headquarters at the As-Saliyah base, outside Doha, Qatar. (AP Photo/Luke Frazza, Pool)