UPDATE 2-Trump says U.S. to exit nuclear treaty, Russia says dangerous move

President Donald Trump said on Saturday the United States will exit the Cold-War era treaty that eliminated a class of nuclear weapons due to Russian violations, a move an official in Moscow called a dangerous attempt at blackmail.

The Intermediate-Range Nuclear Forces Treaty, negotiated by then-President Ronald Reagan and Soviet leader Mikhail Gorbachev in 1988, required the elimination of short-range and intermediate-range nuclear and conventional missiles by both countries.

"Russia has not, unfortunately, honoured the agreement so we're going to terminate the agreement and we're going to pull out," Trump told reporters after a rally in Nevada.

Washington believes Moscow is developing and has deployed a ground-launched system in breach of the INF treaty that could allow Moscow to launch a nuclear strike on Europe at short notice. Russia has consistently denied any such violation.

Trump said the United States will develop the weapons unless Russia and China agree to a halt on development.

China is not a party to the treaty and has invested heavily in conventional missiles as part of an anti-access/area denial strategy, while the INF has banned U.S possession of ground-launched ballistic missiles or cruise missiles of ranges between 500 and 5,500 km (311 and 3,418 miles).

Trump's national security adviser, John Bolton, will visit Moscow next week.

Russia's deputy foreign minister, Sergei Ryabkov, in comments reported by TASS news agency, said a unilateral U.S. withdrawal from the treaty "would be a very dangerous step."

Ryabkov was also quoted as saying that it was Washington and not Moscow that was failing to comply with the treaty.

He said the Trump administration was using the treaty in an attempt to blackmail the Kremlin, putting global security at risk.

"We see an attempt to, effectively, present Russian with an ultimatum," Interfax news agency quoted Ryabkov as saying. "...We will, of course, accept no ultimatums or blackmail methods."

(With inputs from agencies.)