The United States and Russia said Friday they had agreed to maintain the provisions of a major nuclear arms control treaty just hours before the pact expired after being in force for 18 years.
In a joint statement by Russian President Dmitry Medvedev and President Barack Obama, the two sides pledged to continue to work together "in the spirit" of the expiring 1991 Strategic Arms Reduction Treaty.
U.S. and Russian negotiators are working intensively to reach a deal for a successor to the treaty that expired at midnight Greenwich Mean Time, or 7 p.m. EST.
In Friday's statement, the two sides also expressed their "firm intention to ensure that a new treaty on strategic arms enters into force at the earliest possible date."
The U.S.-Russian pledge would appear to mean the two sides will continue to respect the expired treaty's limits on nuclear arms and allow inspectors to continue verifying that both sides were living up to the deal.
White House Press secretary Robert Gibbs said Obama and Medvedev discussed some of the remaining items to be resolved in a phone call Friday.
"We will continue working through the next 24 hours," Gibbs told reporters. But he said it was unlikely that all outstanding issues could be resolved in that time.
Gibbs was asked about European press speculation that Obama will make a side trip to Prague next week to sign a START deal with Medvedev before he goes to Oslo, Norway, to collect his Nobel Peace Prize on Dec. 10. But he said, "We'd have to have an advance team somewhere in Europe to do that, and we don't have one."
Negotiators gave up hope months ago of having a new deal ratified and in place before the expiration.
Ratification of a new deal by Congress and the Russian Duma is likely to take months. Obama and Medvedev initially had set the expiration date as a target for completing negotiations.
The expiring START treaty, signed by Soviet President Mikhail Gorbachev and President George H.W. Bush, required each country to cut its nuclear warheads by at least one-fourth, to about 6,000, and to implement procedures for verifying that each side was sticking to the agreement.
Negotiators still are grappling over verification procedures for the new treaty, which have become the final sticking point preventing a deal.
The Obama administration would welcome a quick conclusion to demonstrate an improvement in U.S.-Russian relations and to gain momentum for other arms control and nonproliferation goals. Washington also is looking for cooperation on issues including reining in Iran's nuclear ambitions. However, Russia has fewer incentives for an immediate deal.
Obama and Medvedev agreed at a Moscow summit in July to cut the number of nuclear warheads each possesses to between 1,500 and 1,675 within seven years as part of a broad new treaty.