Accusing Russia of "cheating at its arms control obligations", Pompeo told a news conference in Brussels that Russia has 60 days to return to compliance with the treaty, after which time the United States would suspend its own compliance.
China, North Korea, and Iran are not obligated by the treaty's limitations, and, "This leaves them free to build all the intermediate range missiles they would like", he said.
This video grab provided by RU-RTR Russian television via AP television on Thursday, March 1, 2018, shows the launch of what President Vladimir Putin said is Russia's new nuclear-powered intercontinental cruise missile.
A state department spokesperson said: "The United States announced a suspension of its obligations, effective 60 days after December 4, unless Russian Federation returns to full and verifiable compliance, as a remedy under customary global law for Russia's material breach".
"The United States declares today it has found Russian Federation in material breach of the treaty and will suspend our obligations as a remedy effective in 60 days unless Russian Federation returns to full and verifiable compliance", Pompeo said at a NATO meeting in Belgium. "They've been violating it for many years", Trump said.
The planned USA withdrawal has created the kind of trans-Atlantic rift that followed Trump's abandonment of landmark worldwide agreements to curb Iran's nuclear program and to fight climate change.
In Moscow, Foreign Ministry spokeswoman Maria Zakharova said that "Russia strictly complies with the provisions of the treaty, and the American side is aware of that". On Nov. 25, Russian border guards fired on three Ukrainian navy vessels near Crimea, where Russia's Black Sea fleet is based.
Stoltenberg said that he regretted seeing the INF come to a close. While it would take a substantial length of time to develop an entirely new missile, existing medium-range weapons in the U.S. arsenal, like sea-launched Tomahawk cruise missiles, could be adapted for ground launch more quickly, arms expert said.
Klimkin welcomed the political support he received in Brussels, but said: "We shouldn't just stay on the level of declarations, however strong declarations are". He added that Russia's actions "greatly undermine America's national security and that of our allies".
"The INF has guaranteed peace and security in European territory for 30 years now", Mogherini said as she arrived for talks with North Atlantic Treaty Organisation foreign ministers. Bolton distributed a memo last week informing government officials to prepare for the immediate withdrawal of the USA from the treaty, but German Chancellor Angela Merkel managed to convince Trump to delay that move.