WASHINGTON — The United States will pull out of a nuclear arms control treaty with Russia, the Trump administration announced Friday, ending a cornerstone Cold War agreement on grounds that Russian violations render it moot.

The demise of the 1987 Intermediate-Range Nuclear Forces (INF) treaty raises fears of a new nuclear arms race, although U.S. officials discount the risk.

Secretary of State Mike Pompeo said the United States is suspending participation in the agreement, starting a six-month countdown to a final U.S. withdrawal. That leaves a slim chance that Russia could end missile programs widely seen as a violation, salvaging the treaty. The United States accuses Moscow of violating the agreement since 2014.”For years Russia has violated the terms of the Intermediate Range Nuclear Forces Treaty without remorse,” Pompeo said, adding that the United States has continued to meet its obligations while seeking to get Moscow to come into compliance.

“When an agreement is so brazenly disregarded and our security is so threatened, we must respond,” he added.

In a statement, President Trump said the onus is on Russia.

“The United States has fully adhered to the INF Treaty for more than 30 years, but we will not remain constrained by its terms while Russia misrepresents its actions,” Trump said. “We cannot be the only country in the world unilaterally bound by this treaty, or any other. 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.”

Earlier Friday, the Kremlin said it expected official notification of the U.S. withdrawal within days.

Kremlin spokesman Dmitry Peskov told reporters Friday that Russia greets the news “with much regret.”

The Associated Press quoted Peskov as saying that Washington has been “unwilling to hold any substantial talks” with Moscow to save the treaty.

The Trump administration has signaled for months that it wants to end the agreement covering ground-based nuclear-tipped cruise missiles.

Arms control specialists said that without the treaty, the United States may move to position missile systems in Europe, while Russia could use the opportunity to base missile systems elsewhere.