Pentagon says 8,500 US troops are on 'heightened alert' amid Russia-Ukraine crisis

• The US has 8,500 troops on "heightened alert" amid Ukraine-Russia tensions, the Pentagon said Monday.
• Russia has gathered tens of thousands of troops on Ukraine's border in recent months.

The Pentagon on Monday said that 8,500 troops are on "heightened alert" amid growing concerns that a Russian invasion of Ukraine is imminent, but no final decisions to deploy US forces have been made.

"The US has taken steps to heighten the readiness of its forces at home and abroad so they are prepared to respond to a range of contingencies, including support to the NATO Response Force (NRF) if it is activated," Pentagon spokesperson John Kirby said, referencing NATO's rapidly deployable force of 40,000 multinational troops.

Defense Secretary Lloyd Austin has "placed a range of units in the US on a heightened preparedness to deploy, which increases our readiness to provide forces, if NATO should activate the NRF, or if other situations develop," Kirby said, adding, "The number of forces that the secretary has placed on heightened alert comes down to about 8500 personnel."

Kirby also said it's "very clear the Russians have no intention right now of de-escalating."

The Pentagon's announcement on Monday came after reports that President Joe Biden was weighing sending thousands of troops to Eastern Europe with the region on high alert over Russia's posture toward Ukraine.

Russia has gathered more than 100,000 troops at Ukraine's border in recent months. Given Russia invaded Ukraine in 2014 and annexed Crimea, there are serious concerns Moscow is planning another military incursion. Russia has also been supporting rebels in a war against Ukrainian forces in the eastern Donbass region since 2014.

The Kremlin has said it doesn't plan to invade, while also resisting calls from Western leaders to pull its forces back from the Ukrainian border.

The Biden administration has warned Russia it will face severe economic consequences if it invades, but has ruled out deploying troops to Ukraine given the former Soviet republic is not a NATO member and the US is not obligated to defend it. That said, the administration has provided Ukraine with roughly $400 million in military assistance over the past year, including weapons or lethal aid.

Diplomatic efforts by the US and its allies to stave off a broader confrontation have so far failed to yield any major breakthroughs, and the White House has expressed concerns that a Russian invasion of Ukraine could be imminent.