Fired Russian security chief Alexander Lebed, a bitter critic of President Boris Yeltsin and his government, told members of Congress there is great danger rogue states may hire Moscow's nuclear scientists.

Many scientists who built the former Soviet Union's nuclear arsenal during the Cold War with the United States are out of work or being paid late and are vulnerable to offers from terrorist groups and countries, Lebed said Thursday."These unique experts are seeking their fortune around the world," declared Lebed. "They will do what they can do, and the world will face the problems of nuclear terrorism or nuclear blackmail."

Lebed suggested the United States and Russia work to employ such scientists in peaceful endeavors. "Only then can we sleep soundly," he said.

Lebed, 47, testified before a House National Security subcommittee.

Fired by Yeltsin in 1996, Lebed finished third in the presidential race that year and plans to run again in 2000. He now is running for governor of Krasnoyarsk, a key industrial region in central Siberia.

In a rant against Yeltsin, Lebed told lawmakers that the Russian leader is too unpredictable to have his finger on the nuclear button. In one example, Lebed noted Yeltsin incorrectly called Germany and Japan nuclear powers last year.

Most Russians have dismissed the goofs by the 67-year-old Yeltsin. But Lebed, speaking in Russian, said the increasing incidents suggest Yeltsin cannot be trusted.

"Some statements made by the supreme commander in the past few months . . . indicate a certain inadequacy of the supreme commander," said Lebed. He noted Yeltsin, the defense minister and the chief of staff share the responsibility of deciding whether to launch a nuclear attack.

"Of course, it is quite dangerous when one component of the nuclear button is a person like that," Lebed said of Yeltsin. "And being commander and chief, he would easily make the other two components agree."