WASHINGTON -- In a major increase of U.S. support to Ukraine, President Joe Biden has signed off on sending 31 M1 Abrams tanks to the war-torn country as concerns mount over a new Russian offensive this spring, according to senior administration officials.
"The reason for 31 is because that is how many tanks would constitute a Ukrainian tank battalion," a U.S. official told reporters in a conference call earlier Wednesday. "So we are specifically meeting that requirement."
The president is set to speak at noon ET from White House's Roosevelt Room on the "continued support for Ukraine," as Ukraine's President Volodymyr Zelenskyy has put out a direct appeal for more tanks with a harsh winter and the one-year anniversary of Russia's invasion approaching.
The U.S. announcement about its tank commitment comes the same day Germany has also pledged to send Ukraine 14 of its own Leopard 2 tanks.
Political gymnastics have muddled Ukraine's plea for more tanks as Russia prepares for a spring offensive, with Germany reportedly hesitant to send Leopard 2s until the U.S. promised to send Abrams tanks -- vehicles which Pentagon officials have publicly said weren't suited for the fight.
Biden administration officials had confirmed to ABC News on Tuesday that they were considering sending the Abrams tanks to Ukraine under the Ukraine Security Assistance Initiative. That means the U.S. will arrange for the contracting of the tanks with their manufacturer, which could mean the vehicles will not be able to be fielded for quite some time -- possibly more than a year.
Early Wednesday, Germany confirmed it will supply Ukraine with Leopard 2 tanks and approve requests by dozens of other countries to do the same. The U.K. has also committed 12 of its own Challenger 2 battle tanks, and Poland has asked Germany for permission to send the Leopards it has in stock.
Still, this falls far short of the 300 battle tanks that Zelenskyy has said he needs for the war.
U.S. officials argued that this new shipment of tanks highlights the unity among all allies working to support Ukraine, minimizing the disagreement between the U.S. and Germany on the usefulness of the Abrams vehicles.
Zelenskyy reacted to the tank comittments in a new SkyNews interview.
"I would like to say thank you to Germany, to Britain and to the United States that they made this decision," he said.
Russia reacts: 'Burn up ... like any other'
The Kremlin has downplayed the new supply of tanks, with spokesman Dmitry Peskov saying in his daily briefing on Wednesday that "to supply U.S.-made Abrams tanks to Ukraine won't work, as its initiators overestimate the potential of Ukrainian servicemen."
"I am sure that many specialists overestimate the absurdity of this idea. Simply because it's a rather bad plan in its technological aspects and, most importantly, there is an obvious overestimation of the potential it could add to the Ukrainian Armed Forces. This is yet another profound misconception," he added.
"We have repeatedly said that these tanks will burn up just like any other," Peskov said.
More international commitments coming, official says
Biden planned to call German Chancellor Olaf Scholz, French President Emmanuel Macron and U.K. Prime Minister Rishi Sunak together later this morning, an official said on Wednesday.
"We do expect other nations to announce contributions of additional armored capability, including some that will be readily available for use on the battlefield in the coming weeks," an official said.
Ukraine wants American and German advanced tanks quickly, as they're more advanced than Russia's own.
"Hundreds of thanks are not hundreds of tanks," Zelenskyy said last week. "All of us can use thousands of words in discussions, but I cannot put words instead of the guns that are needed against Russian artillery or instead of the anti-aircraft missiles that are needed to protect people from Russian air strikes."
An Biden official acknowledged that delivering the Abrams tanks "will take some time," without getting into a specific timeframe, but did say it would take "months, as opposed to weeks."
The Biden administration last week had announced another huge military aid package for Ukraine -- including close to 150 more armored vehicles -- but not the Ukraine-requested tanks.
ABC News' Libby Cathey, Shannon K. Crawford, Luis Martinez, Matt Seyler and Joseph Simonetti contributed to this report.