The United States and Russia said Friday that they had agreed to maintain the provisions of a major nuclear arms control treaty hours before it is set to expire. In a joint statement by Russian President Dmitry Medvedev and US counterpart Barack Obama, the two sides pledged to continue to work together "in the spirit" of the expiring 1991 Strategic Arms Reduction Treaty. Meanwhile, US and Russian negotiators are working intensively to reach a deal for a successor treaty. In Friday's statement, the two sides also express their "firm intention to ensure that a new treaty on strategic arms enters into force at the earliest possible date." The US-Russian pledge would appear to mean that the two sides would continue to respect the expiring limits on arms and to allow inspectors to continue verifying that both sides are living up to the deal. Neither the US nor Russia anticipates security problems after the expiration. Negotiators had given up hope months ago of having a new deal ratified and in place before the expiration at midnight Greenwich Mean Time. 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. The legal basis for the procedures, including inspections of nuclear facilities, also will expire Friday. The State Department said this week that it believes the two sides can keep some of the verification procedures in place through an informal political agreement that is not legally binding. 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 US-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. The Obama administration also had held out hope that a deal could be sealed in time for Obama's trip to Europe to accept the Nobel Peace Prize on Dec. 10. It appears unlikely, however, that a breakthrough will happen by then.