An undisclosed number of Fort Carson troops have been placed on “increased readiness” to deploy to Ukraine, should Russia invade, along with troops from at least nine other U.S. military installations, the Pentagon said Thursday.

Among the 8,500 troops placed on prepare to deploy orders by Secretary of Defense Lloyd J. Austin III are soldiers out of the 82nd Airborne at Fort Bragg, N.C., which regularly maintains high readiness, in addition to troops from the post’s 18th Airborne Corps — as well as soldiers from Kentucky-based Fort Campbell’s 101st Airborne Division and the Mountain Post’s 4th Infantry Division, according to a news release from the Department of Defense.

The troops represent combat, medical, aviation and logistical elements, Pentagon Press Secretary John Kirby said.

Additional units will heighten readiness, including those from Davis-Monthan Air Force Base in Arizona, where A-10 Thunderbolt close air support aircraft are based; Fort Hood in Texas; Joint Base Lewis-McChord in Washington; Fort Polk in Louisiana; Robins Air Force Base in Georgia, which houses a major logistics complex; Fort Stewart in Georgia; Wright-Patterson Air Force Base in Ohio; and other locations throughout the U.S., he added.

“We still believe there’s time and space for diplomacy,” Kirby said. “But thus far, it has not achieved the kind of results that the international community would like to see.”

U.S. forces in Europe, already on heightened readiness status, may be used to bolster support to NATO allies, he added.

Fort Carson would not divulge additional details Thursday evening, including the number of troops placed on heightened status.

A spokesperson for Peterson and Schriever Space Force bases had no knowledge of any of the installations’ troops being involved.

A spokesperson for the Air Force Academy declined to comment beyond referring to a Jan. 24 press conference held by Kirby that did not list installations of troops placed on heightened alert.

A spokesperson for NORAD and USNORTHCOM had no information to provide outside of the Pentagon’s Thursday announcement.

A spokesperson for Buckley Space Force Base in Aurora did not immediately respond to an email seeking comment.

A spokesman for the Colorado National Guard referred The Gazette to the Department of Defense. A Pentagon spokesperson said no additional information on units and capabilities would be provided Thursday night.

Ukraine crisis splits Congress

The United States and NATO have made no concessions to the main Russian demands to resolve the crisis over Ukraine, including giving Moscow a guarantee that its western neighbor can never join the alliance.

The focus is now on how Russia will respond — a decision that rests squarely with President Vladimir Putin and one that could determine whether Europe will again be plunged into war.

Kremlin spokesman Dmitry Peskov on Thursday told reporters that the response from the U.S. — and a similar one from NATO — leaves “little ground for optimism.”

But he added that “there always are prospects for continuing a dialogue, it’s in the interests of both us and the Americans.”

President Joe Biden warned Ukrainian President Volodymyr Zelenskyy on Thursday that there is a “distinct possibility” that the Russians could invade Ukraine in February, according to White House National Security Council spokesperson Emily Horne.

The exchange happened in a call between the two leaders that was described by the White House as a “check in” to discuss the latest diplomatic efforts.

“He has said this publicly and we have been warning about this for months,” Horne said of Biden’s latest comments about rising U.S. concern of a further invasion by Russia of Ukraine.

Biden warned Zelenskyy that the U.S. believed there was a high degree of likelihood that Russia could invade when the ground freezes and Russian forces could attack Ukrainian territory from north of Kyiv, according to two people familiar with the conversation who were not authorized to comment and spoke on the condition of anonymity.

Military experts have said Russia may be waiting for optimal ground conditions to move heavy equipment into Kyiv as part of any invasion. Eight years ago, Russia invaded Ukraine’s Crimean Peninsula in late February.

The White House said in a separate statement that Biden also “reaffirmed the readiness” of the U.S. and allies “to respond decisively” if Russia further invades Ukrainian territory.

The U.N. Security Council will hold an open meeting Monday on what U.S. Ambassador Linda Thomas-Greenfield called “Russia’s threatening behavior against Ukraine and the build-up of Russian troops on Ukraine’s borders and in Belarus.”

She said Thursday that the deployment of more than 100,000 troops on the Ukrainian border and other destabilizing acts aimed at the country pose “a clear threat to international peace and security and the U.N. Charter.”

The Associated Press and Gazette military editor David Bitton contributed to this report.