WASHINGTON: President Joe Biden has approved the deployment of nearly 3,000 American troops to eastern Europe in the coming days amid a standoff with Russia over Ukraine in what the Pentagon said on Wednesday was signal of U.S. readiness to defend NATO allies.

The deployments are above and beyond the 8,500 troops the Pentagon put on alert last month to be ready to deploy to Europe if needed. Together, the moves aim to reassure jittery NATO allies in the face of a Russian military buildup near Ukraine while avoiding new deployments to Ukraine itself, which is not part of NATO.

A source familiar with the details said 1,700 would deploy from Fort Bragg in North Carolina to Poland and another 300 from the base to Germany. About 1,000 Germany-based troops would to head to Romania, the source said.

The Pentagon said it was not ruling out additional deployments beyond those announced on Wednesday.

"It's important that we send a strong signal to Mr. Putin and, frankly, to the world that NATO matters to the United States and it matters to our allies," Pentagon spokesman John Kirby said at a news briefing, referring to Russian President Vladimir Putin.

The U.S. troops notified of ready-to-deploy orders last week included additional brigade combat teams, logistics personnel, medical support, aviation support and forces involved with intelligence, surveillance and reconnaissance missions.

Russia denies planning an invasion. But, having engineered the ongoing crisis by surrounding Ukraine with forces from the north, east and south, Moscow is now citing the Western response as evidence to support its narrative that Russia is the target, not the instigator, of aggression.

Russia, which seized Crimea from Ukraine in 2014 and backs pro-Russian rebels fighting government forces in eastern Ukraine, is demanding sweeping security guarantees including a promise that NATO never admit Ukraine.

The United States has dismissed such calls, saying it would be up to Ukraine and to NATO whether Kyiv ever joins the alliance.

The Pentagon renewed warnings about Russia's buildup but held out hope that Putin would opt for a diplomatic solution to the crisis.

"We still don't believe he's made a decision to further invade Ukraine," Kirby said.