U.S. National Security Advisor John Bolton is holding talks in Moscow after the Russian government condemned Washington for pulling out of a key nuclear treaty.
President Trump said he is pulling the U.S. out of the 1987 Intermediate-Range Nuclear Forces pact because Russia was violating it - accusations Moscow denies.
Bolton is scheduled to meet President Vladimir Putin, which will likely take place on Tuesday.
Putin's spokesman Dmitry Peskov said the Russian leader was looking for clarifications about U.S. intentions.