The United States and Russia have ended negotations on new nuclear weapons reductions, dpa quoted the US State Department as saying today, missing a goal to reach an agreement by the end of the year. The US delegation led by Assistant of State Secretary Rose Gottemoeller returned over the weekend from Geneva, which has been the site of more than two months of intense negotiations toward a successor to the 1991 START pact, or Strategic Arms Reduction Treaty. "Our goal remains to conclude a solid treaty for the president"s signature as soon as possible, and we expect that the teams will resume their negotiations in Geneva in mid-January," State Department spokesman PJ Crowley. START expired on December 5, the original target date for a new treaty set by both sides. Washington and Moscow have pledged to adhere to START in the interim. The two countries expressed hope for an agreement to further reduce nuclear stockpiles by the end of this year. Presidents Barack Obama and Dmitry Medvedev met on the sidelines of climate change talks in Copenhagen last week and were optimistic they were "close" to a successor to START, saying there were some small technical issues still to be worked out. US and Russian representatives are said to be hung up on issues of verification of compliance to a new treaty. "The issues that we"re working through in terms of numbers and verification and, and the complex issues regarding these kinds of systems, it does take significant time to work through," Crowley said. "It"s very, very complex." The goal of the new accord is reportedly to cut the number of nuclear warheads to a maximum of 1,675 per country, while limiting delivery systems to 1,100 each. Any new treaty would have to be ratified by the US Senate and Russian Duma.