WASHINGTON - Hoping to salvage his arms control legacy, President Obama called Monday for the renewal of a major post-Cold War agreement between the United States and Russia to secure and dismantle nuclear weapons left over from the former Soviet Union.

In an appeal aimed at Russia, Obama offered to renegotiate terms of the 20-year-old threat reduction initiative known for its chief sponsors, former Sen. Sam Nunn and outgoing Sen. Richard Lugar, and use it as a template for future U.S. cooperation with Moscow.

"Let's update it," Obama told an arms control symposium at the National War College in his first comments on foreign policy since he was re-elected. "Let's work with Russia as an equal partner. Let's continue the work that's so important to the security of both our countries, and I'm optimistic that we can. And we have to keep creating new partnerships."

Russian officials have said they want to end their participation in the Nunn-Lugar agreement, which helped rid the world of more than 7,500 nuclear warheads, plus hundreds of intercontinental missiles, bombers and submarines, from a half dozen former Soviet republics.

The pact was forged after the 1991 collapse of the Soviet Union, which splintered into smaller independent states and left behind a widely scattered nuclear arsenal. Russian officials complain that the agreement hasn't kept pace with changing relations between Washington and Moscow. They object to requirements for Western financing and inspections, for example.

The president didn't provide any details, or hint at whether he would push to negotiate deeper cuts in the nuclear arms stockpiles or seek Senate ratification of the Comprehensive Test Ban Treaty. Congressional resistance has grown since President Bill Clinton failed to win passage.

The Nunn-Lugar program has been a crucial part of U.S.-Russian relations over the last two decades, and its collapse would mark a serious blow to Obama's attempts to improve relations with Moscow and his own attempts to reduce the threat of nuclear war.

Obama advocated for a world without nuclear weapons when he served in the U.S. Senate, but he failed to achieve significant progress during his first term in the White House. His comments Monday reassured the arms control community that he remains committed to the objective even though he did not provide a road map or new set of policy goals for his second term.

Despite the Russian threat to let the program expire next spring, U.S. officials believe Russia may prefer to reshape the joint effort rather than abandon it. However, Moscow is likely to strongly resist U.S. efforts to reduce its battlefield-size, or "tactical" nuclear weapons. Russia also is looking for leverage to stop U.S.-backed plans to build missile defense systems in Eastern Europe, which it views as a threat to its military deterrence capabilities.