The United States and Russia have made progress towards a deal to cut their huge arsenals of nuclear weapons and will hold another round of negotiations in Geneva from Sept. 21, Reuters quoted a U.S. spokesman as saying today. Russian Foreign Minister Sergei Lavrov was also quoted by local news agencies as saying on Thursday that the two sides had narrowed their differences. U.S. President Barack Obama and Kremlin chief Dmitry Medvedev agreed in July the outlines of a preliminary deal to replace the landmark 1991 Strategic Arms Reduction Treaty (START-1) which expires in December. "The talks continued to progress," said a U.S. spokesman at the diplomatic mission in Geneva, referring to the latest closed-door session held from Aug. 31-Sept. 2 in the Swiss city. "The delegations focused on preparing the text of the new treaty, and the work schedule for the next round of talks which will begin on September 21 in Geneva," he added. Lavrov said that negotiators had made progress on difficult issues and would report to both presidents when they meet on the sidelines of the G20 summit in Pittsburgh later this month. He said he was confident that a replacement to the START treaty would be found before the original agreement expired. Finding agreement on a successor agreement for START-1, signed by George Bush and Mikhail Gorbachev just months before the end of the Cold War, is seen by both sides as a way to "reset" relations after the friction of recent years. But many hurdles remain before a deal can be signed, including U.S. plans to deploy missile defence units in Europe.