• The Biden administration will send 31 M1A1 Abrams tanks to Ukraine as the country prepares for a fresh Russian offensive in the coming months.
• The move is a reversal after the U.S. hesitated for weeks to arm Kyiv with tanks.
• The development came as Germany also moved to send tanks to help Ukraine in its fight.

WASHINGTON – The Biden administration announced Wednesday it will equip Ukraine with the mighty M1A1 Abrams tank, a key reversal in the West's effort to arm Kyiv as it prepares for a fresh Russian offensive.

The 31 M1A1 Abrams tanks, which amount to one Ukrainian tank battalion, will expand on the more than $27 billion the U.S. has committed to Kyiv's fight since Russia invaded nearly a year ago.

The tanks will "enhance Ukraine's capacity to defend its territory and achieve its strategic objectives," President Joe Biden said from the Roosevelt Room of the White House.

"Delivering these tanks to the field is going to take time. Time that we'll see and we'll use to make sure the Ukrainians are fully prepared," he said.

Biden later added: "That's what this is about: helping Ukraine defend and protect Ukrainian land. It is not an offensive threat to Russia."

The U.S. will also provide eight M88 recovery vehicles that support the M1A1 Abrams in its latest security package, which is worth approximately $400 million.

Washington plans to purchase the new M1s using funds from that package, the congressionally approved Ukraine Security Assistance Initiative.

It will "take some time" for the tanks to be delivered to Ukraine, a senior Biden administration official said Wednesday. "We are talking months as opposed to weeks," said the official, who spoke on the condition of anonymity, ground rules set by the administration.

The Pentagon has been tasked with providing the training, maintenance and logistics support for the M1A1 tanks, according to the official. Another U.S. official said that the training on how to use the tanks, which will take several months, will occur outside of Ukraine.

National Security Council spokesman John Kirby said Wednesday the Pentagon does not have extra tanks to pull from its current arsenal.

"We just don't have them," Kirby said, adding that "even if there were excess tanks it would still take many months anyway." He also declined to provide a timeline of when the M1A1 Abrams tanks would be ready for Ukrainian forces.

The sudden U.S. about-face follows weeks of hesitation on whether to send the tanks. The administration mulled whether they would offer Ukraine an advantage because they take significant effort to maintain.

"The real challenge with giving the Ukrainians M1A1 tanks is not fuel but maintenance," Jeffrey Edmonds, a Russian military expert at nonprofit national security research group CNA, told CNBC.

"Each system on the tank, from the turbine engine to the complex sights used by the gunner, is complex, requiring numerous intricate parts to function properly," added Edmonds, who has a military career spanning more than two decades.

Edmonds, who spent seven years of service on M1A1 Abrams tanks, said that the platform has specific parts that "are not interchangeable with other tanks and their maintenance is a skill in and of itself."

U.S. officials shared similar concerns for weeks at the departments of State and Defense and White House podiums, and also during Secretary of Defense Lloyd Austin's recent trip to Germany.

"The M1 is a very capable battlefield platform and it's also a very complex capability. And so, like anything that we're providing to Ukraine, we want to ensure that they have the ability to maintain it, sustain it, to train on it," Pentagon press secretary U.S. Air Force Brig. Gen. Pat Ryder told reporters Tuesday.

On Wednesday, a U.S. official said the decision to send the Abrams tanks reflected an evolution in what Ukraine needed on a shifting battlefield.

"This decision is very much in keeping with a constant conversation with allies and partners and of course with Ukraine," the official said

At close to 70 tons, the stalwart M1A1 Abrams is among the heaviest tanks in the world. It makes up for its weight with remarkable firepower and unnerving maneuverability.

Built by General Dynamics Land Systems, the M1 Abrams serves as the U.S. Army's main battle tank. It has been used in nearly every major U.S. conflict since its introduction in 1980.

Ukrainian President Volodymyr Zelenskyy thanked Biden via Twitter saying that the transfer of M1A1 Abrams tanks is, "an important step on the path to victory."

"Today the free world is united as never before for a common goal – liberation of Ukraine," he added.

The addition of the U.S. tanks to the latest military aid package follows German Chancellor Olaf Scholz's decision to provide Ukraine with Leopard 2 tanks.

Germany said its goal was to "quickly assemble two tank battalions with Leopard 2 tanks for Ukraine." The country will supply 14 Leopard 2 A6 tanks in what it called a "first step."

The training of the Ukrainian crews is set to begin quickly in Germany.

One senior U.S. Biden administration official said that Washington expects and welcomes the arrival of hundreds of armored vehicles and tanks in Ukraine from Western allies in the coming months.

'Blatant provocation'

The Kremlin slammed the potential weapons transfer on Tuesday, and said it will not "prevent Russia from reaching our goals."

Kremlin spokesman Dmitry Peskov condemned the expected U.S. announcement, saying, "Unfortunately more weapons from NATO bring more suffering for people in Ukraine."

"It also brings more attention to the continent but it cannot prevent Russia from reaching our goals," he added.

Russia's ambassador to the U.S., Anatoly Antonov, said the tanks "would be another blatant provocation against the Russian Federation."

"If a decision to transfer to Kyiv M1 Abrams is made, American tanks without any doubt will be destroyed as all other samples of NATO military equipment," he said.