Secretary of State Mike Pompeo announced Friday that the U.S. is pulling out of a major arms-control treaty with Russia.

Citing alleged violations by Russia regarding the pact that's been a centerpiece of arms control since the Cold War, Pompeo said the U.S. is suspending its obligations and will terminate the deal entirely if Russia does not return to full compliance in six months.

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He said the U.S. "has fully adhered" to the pact for more than 30 years, "but we will not remain constrained by its terms while Russia misrepresents its actions. We cannot be the only country in the world unilaterally bound by this treaty, or any other."

The American withdrawal had been expected. It follows years of unresolved disputes over Russian compliance with the 1987 pact, known as the Intermediate-Range Nuclear Forces, or INF, treaty. It was the first arms control measure to ban an entire class of weapons: ground-launched cruise missiles with a range between 310 miles and 3,400 miles. Russia denies that it has been in violation.

U.S. officials also have expressed concern that China, which isn't part of the treaty, is deploying large numbers of missiles in Asia that the U.S. can't counter because it's bound by the treaty.

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Sen. Jim Risch, R-Idaho, chairman of the Senate Foreign Relations Committee, backed the Trump administration after Friday's announcement.

“I support the withdrawal of the United States from the Intermediate-Range Nuclear Forces Treaty. ... For the past several years, the Russian government has systematically violated the INF Treaty and deployed systems that undermine the stability that the treaty helped create. Russian actions represent a material breach of the treaty, and it is abundantly clear: the United States is the only country limited by the INF Treaty," he said in a statement.

“The Russian government has had endless opportunities to change their bad behavior, and over the past 60 days has proven its disinterest in doing so. The time has come to set the treaty aside and develop alternative avenues toward the security the treaty once provided.”

NATO also said Russia is in breach of the pact, urging Moscow to come back into compliance during the six months that remain before the United States abandons it. NATO said that if Moscow fails to destroy all new missile systems that Washington insists violate the treaty, "Russia will bear sole responsibility for the end of the treaty."

The Associated Press contributed to this report.