U.S. National Security Advisor John Bolton answers questions from reporters after announcing that the U.S. will withdraw from the Vienna protocol and the 1955 "Treaty of Amity" with Iran during a news conference in the White House briefing room in Washington, U.S., October 3, 2018. REUTERS/Jonathan Ernst

MOSCOW (Reuters) - The United States has yet to finalize its position on extending the New START arms control treaty which is due to expire in 2021, President Donald Trump’s national security adviser John Bolton said on Monday, according to the Russian news agency RIA.

Bolton’s comments, made during a trip to Russia, come after Trump said Washington would withdraw from another agreement, the Intermediate-Range Nuclear Forces Treaty, triggering a warning of retaliatory measures from Moscow.