Russian-American military exercises that have met with opposition from nationalists here should be conducted in the United States rather than in the Ural Mountains, top legislators of both countries proposed Tuesday."It has obviously been a sensitive issue here," U.S. Senator Sam Nunn, chairman of the Armed Services Committee, told a Moscow press conference. "I think that our American people will welcome Russian military force for peacekeeping training."The proposal to move the exercises, first made by Nunn and backed by his Russian counterpart, Sergei Yushenkov, came four days after President Boris Yeltsin formally told U.S. officials he was postponing the maneuvers scheduled for July near the city of Orenberg.The joint exercises, which are not the first of their kind, are largely symbolic, bringing together only 250 soldiers on each side and not involving armored vehicles. Yet they are a visible sign of increased cooperation between the two former Cold War foes, which Russian nationalists say show their country's subservience to foreign interests. Citing this concern, the State Duma, the lower house of parliament, asked Yeltsin in April to reconsider plans to hold the maneuvers in Russia."We can't ignore the internal situation here; there are very strong patriotic forces in the Orenberg region," Yushenkov told reporters after a joint briefing with Nunn. "To conduct exercises where there are masses of people protesting can lead to no good."The presence of U.S. troops on Russian soil has been a sensitive issue ever since the Allied intervention during the Bolshevik Civil War in 1918-1920, but the present-day nationalist opposition took the congressional delegation by surprise."Most of us never had heard of the joint exercises with about 250 troops until Thursday when the Secretary of Defense briefed us on the trip here," Senator James Exon of Nebraska said. "When we came here we found out it was well known, had been debated, was a hot political issue."Nunn said he would be happy to see the exercises take place on a U.S. military base in his native Georgia or another state.Ultimately, the Russian and American presidents, together with their defense ministers, must themselves decide where and when to hold the proposed maneuvers. A spokesman for Yeltsin said on Tuesday evening that there was no official reaction to the proposal yet. Nunn said his group would pitch the idea to President Bill Clinton when the delegation returns to Washington.Nunn, Exon and five other U.S. senators who serve on the armed services committee are in Moscow for talks with their Russian counterparts on such issues as nuclear nonproliferation and arms control, Partnership for Peace, and arms sales.In an interview, Nunn said that one of his growing concerns is Russia's ability to safeguard its nuclear weapons from sabotage or sale abroad by corrupt officials or criminals. An article in the June issue of The Atlantic Monthly raised additional fears by reporting that organized crime in Russia is seeking access to the country's nuclear stockpiles. "I think it's a growing problem even without organized crime; the security of 30,000 nuclear weapons and an awful lot of chemical material is a matter of high priority," Nunn told The Moscow Times. "Organized crime just makes it much more difficult."Nunn, who recently hosted hearings in Washington on Russian organized crime, said, however, that there is no evidence that anyone in Russia has sold weapons-grade nuclear materials. In numerous cases, people have offered such materials but did not deliver the goods, sometimes because of "scams," he added."On nuclear material, all the testimony we have is that there have been sales but not of weapons grade," Nunn said.When the Soviet Union developed its nuclear arsenal, it protected the weapons with the vast apparatus of a police state, from tightly controlled borders to KGB informers throughout society. The collapse of the Soviet police state has left many Western experts worried that nuclear materials spread across a wide network of military bases and laboratories in the former Soviet Union are now vulnerable."We are very much concerned about the fact that much nuclear material -- the makings of a bomb if you will -- are in laboratories in various places in Russia," Exon said. "No one seems to know how much they have and how secure it is."Yushenkov, the head of the State Duma defense committee, said he is not especially concerned by this threat. "I don't see this as a real danger; I think there are enough controls," he said.Yushenkov and other Russian legislators who participated in the two-day meetings complained that the U.S. continues to sell large quantities of arms abroad at the same time they sing the virtues of arms nonproliferation.