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BRUSSELS — Acting Defense Secretary Patrick Shanahan said Thursday that the United States will not withdraw from Afghanistan without consulting NATO allies, and suggested that any coming troop reduction would be coordinated.

"There will be no unilateral troop reduction," Shanahan said in a press conference at the conclusion of a NATO meeting of defense ministers in Brussels.

"That was one of the messages of the meeting today," he said. "It will be coordinated."

Last month, the U.S. began peace talks with the Taliban to try to end a war now in its 18th year. President Donald Trump used his State of the Union address last week to argue “that after two decades of war, the hour has come to at least try for peace.”

"And the other side would like to do the same," Trump said.

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Acting U.S. Defense Secretary Patrick Shanahan gives a press conference following the North Atlantic Council of Defense Ministers, at the NATO headquarters in Brussels, on Feb. 14, 2019. Francois Walschaerts / AFP - Getty Images

There have been roughly 3,500 coalition casualties in Afghanistan, with the United States losing approximately 2,300 troops. U.S. commanders have referred to the conflict as a "stalemate," and the Taliban does not appear to be losing territory 18 months into Trump's new Afghanistan strategy.

On Wednesday, the Taliban said that the talks would resume on Feb. 18 in Islamabad.

Those peace talks, if successful, could lead to a reduction of some of the 14,000 troops that are currently serving in Afghanistan under a NATO mission, according to Jens Stoltenberg, the secretary general of NATO.

The military alliance has "discussed the possibility, of course as part of a peace deal, to reduce the presence of NATO troops" in the country, Stoltenberg told NBC News on Tuesday.

But on Thursday, the top U.S. NATO commander said that troop reductions did not come up in formal discussions during the two-day NATO gathering of defense ministers.

"There’s no plans right now at NATO to withdraw troops," General Curtis Scaparrotti told NBC News. "We came in together, we go out together."

"As an alliance we will collaborate on any changes that might come about here as a result of the peace negotiations that are going," he said.

The decision by the United States to withdraw from the Intermediate-Range Nuclear Forces (INF) Treaty, which bans mid-range missiles, was also a topic for the NATO meeting, as NATO hopes to persuade Russia to comply with the treaty in the next six months.

“Day to day, what we do, is deter our adversaries, deter Russia and defend the Euro-Atlantic, and that’s what we’ll continue to do, and I’m confident that we can continue to do so,” said Scaparrotti.