ELKO, Nevada — President Donald Trump says his intention to scrap a landmark arms control agreement with Russia follows years of violations by Moscow in developing prohibited weapons, and “we’re not going to be the only one to adhere to it.” The Kremlin said the pullout “would be a very dangerous step.”

Members of Congress offered no unified response, with reaction ranging from “a big, big mistake” to “absolutely the right move.”

A split emerged among U.S. allies in Europe: Britain said it stood “absolutely resolute” with the U.S., while Germany called Trump’s move “regrettable.”

The 1987 Intermediate-range Nuclear Forces Treaty helps protect the security of the U.S. and its allies in Europe and the Far East. It bars the United States and Russia from possessing, producing or test-flying a ground-launched cruise missile with a range of 300 miles to 3,400 miles.

“Russia has violated the agreement. They have been violating it for many years,” Trump said Saturday after a rally in Elko, Nevada. “And we’re not going to let them violate a nuclear agreement and go out and do weapons and we’re not allowed to.”

The agreement has constrained the U.S. from developing new weapons, but America will begin developing them unless Russia and China agree not to possess or develop the weapons, Trump said. China is not a party to the pact.

“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,” he said.

Sen. Rand Paul, R-Ky., said it was “a big, big mistake to flippantly get out of this historic agreement.” He told “Fox News Sunday” that both sides accuse the other of violations, and he wants “a rational discussion” with experts to see if Washington and Moscow can settle their differences.

The chairman of the Senate Foreign Relations Committee said he hopes Trump’s step is just a negotiating maneuver. Sen. Bob Corker told CNN’s “State of the Union” that “this could be something that’s just a precursor to trying to get Russia to come into compliance.”

Corker, R-Tenn., said he hopes “we’re going to be able to figure out a way to stay within the treaty.”

But backing Trump was Sen. Lindsey Graham, R-S.C., who said on Fox News: “Absolutely the right move,” adding that “the Russians have been cheating.”

Trump is sending his national security adviser, John Bolton, to Moscow for meetings with Russian leaders, including Foreign Minister Sergei Lavrov and Security Council Secretary Nikolai Patrushev, and was expected to relay the news about Trump’s decision.

“This would be a very dangerous step,” Russia’s deputy foreign minister, Sergei Ryabkov, was quoted as telling state news agency Tass on Sunday. He said a U.S. withdrawal “will cause the most serious condemnation from all members of the international community who are committed to security and stability.”

Germany’s foreign minister, Heiko Maas, said Trump’s move was “regrettable,” the treaty was “an important pillar of our European security architecture” and a pullout “raises difficult questions for us and Europe.” Maas also said Germany has repeatedly urged Moscow to “clear up the serious allegations of breaching the INF treaty, which Russia has so far not done.”

But Britain’s defense secretary, Gavin Williamson, said his country stands “absolutely resolute” with the United States on the treaty dispute. Williamson blamed Russia for endangering the arms control pact and he called on the Kremlin to “get its house in order.”

Williamson told the Financial Times on Sunday that Moscow had made a “mockery” of the Intermediate-Range Nuclear Forces Treaty.

U.S.-Russia relations already are strained as a result of the Ukrainian crisis, the war in Syria and allegations of Russian meddling in the 2016 presidential race and upcoming U.S. midterm elections.

Trump did not provide details about violations.