Defense Secretary Donald H. Rumsfeld will take the war on terrorism to the Middle East in a series of talks with leaders there, he announced Tuesday.

Rumsfeld's meetings with key allies in Saudi Arabia, Oman, Egypt and Uzbekistan could prove to be the most critical stage yet in the plans Washington has for retaliation for the Sept. 11 attacks on the World Trade Center, the Pentagon and a hijacked jetliner that crashed in rural Pennsylvania.

Rumsfeld said he hoped his first face-to-face meeting with Uzbek leaders would be useful, since Uzbekistan borders Afghanistan, where terrorist suspect Usama bin Laden is being sheltered by the Taliban government.

He said he also would meet with U.S. troops performing joint exercises in Egypt.

The trip, requested by President Bush, will revolve around "a series of meetings on defense-related efforts in the war on terrorism" and discuss other topics," Defense Department spokeswoman Victoria Clarke said.

Rumsfeld was to leave late Tuesday evening.

"This is to continue the consultations that have already started," Clarke said.

Asked why Bush chose to send Rumsfeld to the region rather than Secretary of State Colin Powell, White House spokesman Ari Fleischer replied, "Because he's the appropriate person to go."

Many of the U.S. forces in the region are based in Saudi Arabia, and others are in smaller Persian Gulf countries such as Bahrain and Kuwait. Saudi officials reportedly have expressed reservations about the use of bases on their soil to launch retaliatory strikes against bin Laden and his Al Qaeda network.

Support for the anti-terrorism campaign in Muslim countries is considered important to counter claims by bin Laden supporters that the United States is waging war against Islam.

"We want to make sure we have the consultations at the highest level," Clarke said. "It's a very strong sign of the importance we place on the region and on the coalitions."

The trip was announced as U.S. allies are beginning to solidify behind the evidence Washington has put forward linking bin Laden to the attacks. British Prime Minister Tony Blair and NATO Secretary-General Lord Robertson both said they've been shown clear and convincing evidence that bin Laden and the Al Qaeda were behind the attacks, which killed an estimated 6,000 people.

Clarke declined to say whether Rumsfeld would provide the same information to the Middle Eastern officials he'll meet.

Rumsfeld's trip comes as the U.S. continues to beef up its military presence in the region. Clarke said that about 30,000 American military members are in the region, including two aircraft carrier battle groups and 350 planes.

In addition to the naval forces in the Persian Gulf and Arabian Sea, the Pentagon has dispatched more than 100 additional Air Force planes to the region since the Sept. 11 terrorist attacks. They are based in Saudi Arabia, Kuwait, Bahrain and other Gulf nations.

Two other aircraft carriers are at sea and under way to the region.

The USS Kitty Hawk, which departed its homeport in Japan on Monday, will be available in or near the Arabian Sea as a floating base for other forces, defense officials said. An aircraft carrier normally has about 75 Navy planes on board for a variety of missions, including fighters for land attack. The Kitty Hawk carried less than its full complement, prompting speculation that it was making space for helicopters for use in special-operations missions.

Two defense officials, speaking on condition of anonymity, said the Kitty Hawk was headed toward the Arabian Sea to be available for use by U.S. special operations forces or by Navy aircraft other than its own.

Lt. Cmdr. Jeff Gordon, a spokesman at Pacific Fleet headquarters in Hawaii, said the Kitty Hawk left a portion of its air wing behind at Atsugi Air Base in Japan when it departed. He said he could not provide more details.

One defense official, speaking on condition of anonymity, said the Kitty Hawk left Yokosuka Naval Base outside of Tokyo with a "representative mix" of strike and support planes on board, including combat aircraft like the F-18 Hornet and F-14 Tomcat. He would not say how many planes were on board but made clear it was much fewer than normal.

A carrier has fighter aircraft aboard not only for offensive strikes but also to help defend itself.

Other than Afghanistan, U.S. officials have refused to discuss which nations might be military targets.