U.S. National Security Advisor John Bolton faces tough questions this week in Moscow after President Trump said he will pull the U.S. out of a key Cold War arms deal with Russia.
Bolton will meet with Russian Foreign Minister Sergey Lavrov Monday and President Vladimir Putin Tuesday.
Trump has accused Russia of building and testing missiles that violate the 1987 Intermediate-Range Nuclear Forces Treaty – better known as the INF pact.
The landmark deal bans the U.S. and Russia from building, testing, and stockpiling ground-launched nuclear missiles with a range from 500 to 5,000 kilometers.
The Kremlin has yet to formally comment on Trump's announcement other than saying "explanations...will be required."
Former Soviet president Mikhail Gorbachev signed the deal with the late U.S. president Ronald Reagan at the White House in 1987.
"Do they really not understand in Washington what this could lead to?" Russia's Interfax news agency quoted Gorbachev as saying. "Washington's desire to turn back politics cannot be supported. Not only Russia, but all those who cherish the world, especially a world without nuclear weapons, must declare this."
Russian Deputy Foreign Minister Sergei Ryabkov told Tass news agency that the U.S. move would be "a very dangerous step."
Without specifying how Russia violated the treaty, Trump Saturday appeared to say Moscow will not get away with it.
"Russia has violated the agreement. They have been violating it for many years. And we're not going to let them violate a nuclear agreement and go out and do weapons and we are not allowed to," he said.
U.S. officials going back to the Obama administration have accused Russia of deliberately deploying a land-based cruise missile to pose a threat to NATO.
Russia has denied violating the INF agreement and says U.S. missile defense systems are a violation.
Many so-called hawks in Washington say the INF treaty keeps the U.S. from developing a new generation of weapons in a world that faces new global security challenges.
"We'll have to develop those weapons, unless Russia comes to us and China comes to us and they all come to us and say let's really get smart and let's none of us develop those weapons, but if Russia's doing it and if China's doing it, and we're adhering to the agreement, that's unacceptable," Trump said.
China is not part of the IMF agreement.
Beatrice Fihn, the executive director of the International Campaign to Abolish Nuclear Weapons – the coalition that won the 2017 Nobel Peace Prize – said that "by declaring he will leave the INF Treaty, President Trump has shown himself to be a demolition man who has no ability to build real security. Instead, by blowing up nuclear treaties, he is taking the U.S. down a trillion dollar road to a new nuclear arms race."
Dmitry Oreshkin, an independent Russian political analyst told the Associated Press, "We are slowly slipping back to the situation of Cold War, as it was at the end of the Soviet Union, with quite similar consequences, but now it could be worse because Putin belongs to a generation that had no war under its belt. These people aren't as much fearful of a war as people of (former Soviet leader Leonid) Brezhnev's epoch. They think if they threaten the West properly, it gets scared."