WASHINGTON  Vice President Dick Cheney on Thursday vigorously defended the use of harsh interrogation techniques on a few suspected terrorists, saying that the methods made up “a tougher program, for tougher customers” and might have averted another attack on the United States.

“A small number of terrorists, high-value targets, held overseas have gone through an interrogation program run by the C.I.A.,” Mr. Cheney said in an address to the Conservative Political Action Conference in Washington, around the same time that the head of the Central Intelligence Agency said one of the most controversial interrogation methods, “waterboarding,” may be illegal under current law.

The “high-value targets” included Khalid Shaikh Mohammed, the mastermind of the Sept. 11, 2001, terrorist attacks, Mr. Cheney recalled. “He and others were questioned at a time when another attack on this country was believed to be imminent. It’s a good thing we had them in custody, and it’s a good thing we found out what they knew,” the vice president said, drawing applause.

Mr. Cheney did not use the term “waterboarding,” which simulates the feeling of drowning in the subject. But the C.I.A. director, Michael V. Hayden, acknowledged recently that Mr. Mohammed was one of three suspects on whom the harsh technique was used several years ago.