A day after she invited Russia for more cooperation with NATO,US Secretary of State Hillary Clinton on Wednesday called her Russian counterpart Sergey Lavrov and discussed the ongoing START negotiations between the two countries and other bilateral issues. The telephonic conversation between the two leaders lasted for 15 minutes during which the Secretary of State emphasised to Lavrov that their negotiators were close to reaching an agreement. She asked his Russian counterpart to wrap up the negotiations quickly with the US over a key nuclear arms reduction treaty that expired in December. "Clinton encouraged Russia to continue to move ahead push hard so that the two countries can reach an agreement on Strategic Arms Reduction Treaty (START) in next couple of weeks," Assistant Secretary of State for Public Affairs P J Crowley said. President Barack Obama and Russian President Dmitry Medvedev agreed in July to cut the number of nuclear warheads each country has to between 1,500 and 1,675 under a new treaty. "They also talked about the prospect of getting together in the very near future as part of the Quartet to focus on the Middle East," he said.