The United States announced on Friday that it is suspending a landmark arms control treaty with Russia and will withdraw from the pact in six months if Moscow does not end its alleged violations.
The US made the decision because of the development of Moscow's 9M729 land-based cruise missile system, which it claims violates the terms of the historic agreement.
"For far too long, Russia has violated the Intermediate-Range Nuclear Forces (INF) Treaty with impunity, covertly developing and fielding a prohibited missile system that poses a direct threat to our allies and troops abroad," US President Donald Trump said in a statement.
He added that the US would suspend its obligations under the treaty and begin the process of withdrawing from it on Saturday.
The withdrawal process "will be completed in 6 months unless Russia comes back into compliance by destroying all of its violating missiles, launchers, and associated equipment," the statement added.
The deal, signed in 1987 by then-US president Ronald Reagan and Soviet leader Mikhail Gorbachev, bans the production, testing and deployment of land-based cruise and ballistic missiles with a range of 500 to 5,500km.
Russia last week showed off the controversial missile system to foreign military attaches and journalists, stressing that it had a maximum range of 480km, making it compliant with the INF treaty.
However, Trump accused Russia of misrepresenting its actions and said the US would "not remain constrained" by the terms of the deal if Moscow wasn't adhering to it.
He said the US' NATO allies "fully support" its decision to withdraw from the pact, "because they understand the threat posed by Russia’s violation and the risks to arms control posed by ignoring treaty violations."
"We will move forward with developing our own military response options and will work with NATO and our other allies and partners to deny Russia any military advantage from its unlawful conduct," he said.
The US president added that he was "ready to engage with Russia" on arms control in hopes they could "develop, perhaps for the first time ever, an outstanding relationship on economic, trade, political, and military levels."
"This would be a fantastic thing for Russia and the United States, and would also be great for the world," he said.
Russia's RIA news agency later cited a foreign ministry spokeswoman as saying that Moscow is ready to maintain a dialogue with Washington over the treaty.