PERVOMAISK, Ukraine -- U.S. Defense Secretary William Perry left Ukraine for Belarus on Wednesday, but not before he had seen a long-range monster of the Cold War during an unprecedented visit to a nuclear missile base on Tuesday.


At Ukraine's invitation, Perry flew to this base in fertile fields and walked to the edge of an open concrete silo containing a 30-meter SS-24 intercontinental missile from which 10 warheads had recently been removed.


"This is an historic moment. This has been a fine confidence-building measure," he told Ukrainian Defense Minister Vitaly Radetsky, who had urged Perry to examine at first hand the former Soviet republic's efforts to become a nonnuclear state.


Perry, 66, later said he was struck deeply by the tour, which included observation of two Ukrainian missile launch officers practicing at an underground bunker.


"As I stood there watching this process, I admit that I was awed. These two operators can control almost 800 warheads -- the power to destroy almost every major city in the United States from this one control center," he said.


Perry, nearing the end of a trip to improve U.S. military ties with former Soviet republics, was assured by Radetsky that work to deactivate Ukraine's 46 SS-24s and 130 six-warhead SS-19s was proceeding well. He invited Perry to look into any silo he wanted.


"We'll have a bet on this one," Radetsky said. "If there is a warhead, we'll pay. Otherwise, you pay." That, of course, is what the United States is doing.


Perry defended the cost to U.S. taxpayers. "This seems like a lot of money but it buys us more defense than any other use of defense dollars that I could think of," Perry said.


Perry flew on to Belarus and began talks with Prime Minister Vyacheslav Kebich, who said Belarus would likely announce during Perry's visit it would join NATO's Partnership for Peace.