WASHINGTON -- Russia has given the United States a part of a U.S. spy plane shot down in 1960 as a sign of continuing cooperation despite the recent arrest of a CIA official who allegedly did espionage work for Russia.


The small piece of a U-2 spy plane flown by Francis Gary Powers, who was captured and later released, was exchanged Wednesday by a U.S.-Russian commission investigating the fates of U.S. servicemen in the Soviet Union since World War II.


Last year, the United States gave to Russia a ship's bell from a former Soviet attack submarine that sank accidentally in the Pacific in 1968 and was retrieved later by the United States. Commission officials told a Pentagon news conference Wednesday their POW-MIA search would not be slowed by the Feb. 21 arrest in Washington of Aldrich Ames, the accused Moscow mole inside the CIA, and his wife, Rosario.


"Despite certain unpleasantries, namely the Ames case, that have grabbed headlines in recent weeks, our cooperation on the joint commission continues unabated," said former U.S. Ambassador to Moscow Malcolm Toon.


Toon is joint chairman of the POW-MIA commission along with Russian General Dmitry Volkogonov.


"I am in complete agreement with Ambassador Toon," Volkogonov said. "No sort of temporary slowdown should impede our positive progress forward in cooperation."


Toon said the mounted piece of black-and-yellow metal from Powers' U-2 had been presented to him by Volkogonov along with a picture of the same kind of Soviet anti-aircraft missile that shot down the high-flying spy plane over the Soviet Union.


It was one of 10 such American planes shot down by the Soviet Union during the Cold War. The downing of Powers' U-2 led to a U.S.-Soviet diplomatic crisis which resulted in the cancellation of a planned summit between U.S. President Dwight Eisenhower and the Soviet leader, Nikita Khrushchev.


There was no evidence, they said at the close of the eighth meeting of the two-year-old commission, that any military prisoners from World War II, the Korean War, or Vietnam War were currently being held against their will in the former Soviet Union.


But they said the commission would continue looking for evidence or remains of any U.S. prisoners who might have been previously transferred to the Soviet Union and held there. Last August, a U.S. Defense Department report, confirming long-held suspicions, said "the Soviets transferred several hundred U.S. Korean War POWs to the U.S.S.R. and did not repatriate them," but used them as political hostages, intelligence sources and forced labor.