The United States and Russia are close to completing an agreement designed to limit trafficking in portable air-defense missiles (search), which some security experts fear terrorists could use against commercial airliners, Russian Defense Minister Sergei Ivanov (search) said Tuesday.

At a joint news conference with Defense Secretary Donald H. Rumsfeld (search), Ivanov provided few details but said the proposed accord reflected a common interest between the United States and Russia in constraining the unauthorized movement of these weapons around the world.

"You know full well that terrorists of all hues and stripes" have sought to obtain them, he said.

Ivanov, speaking through an interpreter, said "an agreement on the exchange of information" on portable air-defense weapons would be signed by the two countries "pretty soon."

He said the agreement was put together quickly "because it was in the best interests of both states to maximally constrain" the movement of such weapons, such as the American-made Stinger shoulder-fired missiles the CIA supplied to Afghan rebels fighting Soviet forces in the 1980s.

Ivanov said "negligible amounts" of Russian-made air defense weapons also were in Afghanistan, and they are included in the inventories of many central and eastern European countries.

Rumsfeld did not comment on the deal, and other U.S. officials did not immediately have information about it.

Typically, these relatively cheap weapons are small, rocket-propelled warheads with heat-seeking sensors. They are designed to be triggered from a tube-like, disposable launcher and to follow the heat of a jet engine's exhaust to its source. The CIA-backed rebels in Afghanistan used Stingers to great effect against Russian helicopters and other low-flying aircraft during the 1980s.

Ivanov also said he had accepted a U.S. invitation for Russian forces to participate in a U.S.-based military exercise to "handle nuclear safety issues while transporting nuclear munitions." He did not elaborate, and U.S. officials at the Pentagon did not immediately have any other information.