The United States officially withdrew from a nuclear missile agreement with Russia on Friday after it found that Russia was in violation of the treaty.Russian officials have repeatedly denied violating the agreement.The 1987 Intermediate-range Nuclear Forces Treaty (INF) was signed when Russia was part of the Soviet Union.The treaty banned both sides from deploying land-based missiles able to travel a distance of between 500 and 5,500 kilometers.It reduced the possibility of either side launching a nuclear strike with little warning.Six months ago, the U.S. government said it planned to pull out of the arms control treaty unless Russia honored the agreement.Russia said U.S. officials were making claims simply to justify their desire to withdraw from the treaty."The United States will not remain party to a treaty that is...violated by Russia," Secretary of State Mike Pompeo said in a statement."Russia is solely responsible for the treaty's demise," he added.At the center of the dispute is a U.S. demand that Russia destroy a new missile called the Novator 9M729, known to the NATO military alliance as the SSC-8.NATO says the SSC-8 has a range of about 1,500 kilometers and violates the treaty.Russia refuses to destroy the missiles, and says their range is less than 500 kilometers.U.S. officials who did not want their names used in news reports said Russia had deployed the missilesthroughout Russia "with the ability to strike critical European targets."Also on Friday, Russia said it had asked the United States for a halt on the deployment of short and intermediate-range nuclear missiles in Europe.Deputy Foreign Minister Sergei Ryabkov was reported as saying that Russiahad asked the U.S. and NATO countries to join them in honoring the moratorium.The TASS Russian news service reported his comments.NATO Secretary-General Jens Stoltenberg refused the minister's request on Friday.He said it was "not a credible offer" since Russia had already deployed illegal missiles."There are no new U.S. missiles, no new NATO missiles in Europe, but there are more and more new Russian missiles," Stoltenberg said.U.S. President Donald Trump said he is hopeful a new agreement can be negotiated to replace the 1987 treaty."Russia would like to do something on a nuclear treaty and that's OK with me.They would like to do something and so would I," Trump said to a question from VOA Thursday.But the president said "we didn't discuss the INF" when he spoke to Russian President Vladimir Putin on Wednesday.In his statement, however, Pompeo said Trump was "seeking a new era of arms control."He called on Russia and China "to join us in this opportunity to deliver real security results to our nations and the entire world."At United Nations headquarters in New York, UN Secretary-General Antonio Guterres said that he was concerned about the treaty's expiration."This will likely heighten, not reduce, the threat posed by (nuclear) missiles," he told reporters on Thursday.The treaty has helped to guarantee security in Europe for more than 30 years.It bans the development and deployment of ground-launched nuclear missiles with ranges between 500 and 5,500 kilometers.Many European leaders fear a renewed arms race with the end of the treaty.They called on both the U.S. and Russian governments to work to keep it.