The United States would have stopped the Sept. 11, 2001, terrorist attacks if American intelligence had gotten better inside information on those who planned and carried them out, Defense Secretary Donald H. Rumsfeld (search) told sailors and Marines aboard this warship Friday.

Without directly assigning blame to the CIA, whose director, George Tenet (search), resigned on Thursday and will leave in July, Rumsfeld posed the question, "Is it a terrible failure that we did not" have sufficiently good intelligence to stop the worst terrorist attack ever on American soil?

His answer was that it simply is not possible to prevent every conceivable attack, and that is why the United States has taken a more aggressive approach to disrupting terrorists before they strike.

"We have to be realistic and expect that there will be additional successful attacks," he said during a question-and-answer session with several hundred sailors and Marines aboard the USS Essex (search), a helicopter carrier in port at Singapore with several other ships of the Essex strike group.

"We just need to keep doing everything we can to see there are fewer and fewer of them," he added.

Rumsfeld was in Singapore to attend an international security conference that opened Friday. He is scheduled to deliver a speech Saturday spelling out U.S. security policy in the Asia-Pacific region.

In a brief interview with reporters at his Singapore hotel, Rumsfeld offered high praise for Tenet. He said that by meeting face-to-face frequently, he and Tenet had gotten the defense and the intelligence establishments "knitted together" in closer cooperation than at any recent period.

"I'm going to miss him," he said.

Rumsfeld also met privately at the hotel with his South Korean counterpart, Gen. Cho Young Kil. In a joint written statement issued afterward they said Seoul had reiterated its intention to send 3,000 troops to Iraq soon, and that progress is being made on modernizing the U.S.-South Korean defense alliance.

In an interview later with reporters from Asian news organizations, Rumsfeld disputed reports that a recent U.S. Pacific Command initiative on combatting terrorism at sea was an attempt by the United States to introduce U.S. naval forces into the territorial waters of Asian nations.

"Any implication that it would impinge in any way on the territorial waters of some countries would be inaccurate. It just wouldn't," he said.

Adm. Walter Dornan, commander of the U.S. Pacific Fleet, told reporters that the maritime initiative was simply meant to raise regional awareness of smuggling and other illegal activities at sea and to encourage countries to find ways to share information and combat the problem.

Aboard the USS Essex, Rumsfeld spoke from a flight deck crowded with a variety of attack and transport aircraft. He faced Marines and sailors under a sweltering tropical sun with an MH-60 Seahawk search-and-rescue helicopter and an AV-8B Harrier attack jet parked behind him as props. Within view across the sparkling Singapore Straits was the hazy coastline of Indonesia. Armed maritime patrols ringed the Essex.

When a Marine asked Rumsfeld whether he thought there had been enough intelligence information to prevent the Sept. 11 attacks on the World Trade Center and the Pentagon, Rumsfeld replied that the congressionally chartered commission investigating the matter has not finished its work.

"We lacked the intelligence that might have prevented it," he said, citing testimony given to the commission. "That is to say, we did not have a source inside the group of people that had planned and executed those attacks ... Had we had a source inside there we undoubtedly would have been able to stop it. We did not. It would have been terrific if we had."

Rumsfeld did not mention Tenet. He credited American intelligence with having collected enough intelligence to stop other terrorist attacks, and he said it would have been a "big order" for the intelligence agencies to penetrate every conceivable hostile group prior to Sept. 11, 2001.

The defense secretary also was asked about the government's recent warnings that a terrorist attack could happen this summer in the United States.

"The threat level suggests a good deal of interest on the part of terrorists in attacking the United States," he said, adding he would not predict an attack would happen.

When a Marine asked Rumsfeld when U.S. troops in Southeast Asia would "start hunting some terrorists," Rumsfeld replied, "I would hope pretty soon," adding that much already is being done quietly behind the scenes. It is "kind of misleading" to think the lack of publicity about anti-terrorist efforts means they are not being pursued here, he said.

During his two hours aboard the Essex, Rumsfeld also complained about news coverage of events in Iraq, which he said focused too heavily on the bad news while largely ignoring progress that has been made.

He also told the Marines and sailors the terrorists who seek to destroy the United States and other nations are "zealots and despots," and that at some point they will be called to join the fight.

"You will endure tough moments," he said, adding he was sure they eventually would prevail.