The United States and Russia pledged Tuesday to reduce their stockpiles of long-range nuclear weapons "to the lowest possible" level.

As an outgrowth of the latest round of talks between President Bush and Russian President Vladimir Putin, the two countries also said they were fully committed to preventing the spread of nuclear weapons technology.

A pivotal 1991 treaty called for reduction of long-range U.S. and Russian nuclear missiles by about one-third. It is due to expire in December 2009.

A senior Republican senator, Richard Lugar of Indiana, who specializes in arms control, urged Bush before his talks Monday with Putin in Kennebunkport, Maine, to make sure the treaty was extended with binding language.

In a joint statement issued Tuesday, Secretary of State Condoleezza Rice and Russian Foreign Minister Sergey Lavrov said the two sides intended to carry out strategic offensive reductions "to the lowest possible level consistent with their national security requirements and alliance commitments."

The countries will work toward developing an arrangement "to provide continuity and predictability" about their arsenals, the brief statement said.

Bush and Putin instructed the two sides to produce "early results," the statement said.

On other weapons issues, a declaration released with the joint statement said the United States and Russia would seek the cooperation of other countries to guard against the proliferation of nuclear weapons.

And, the declaration said, the U.S. and Russia would expand their cooperation in the field of using nuclear energy for peaceful purposes.