The Patriot missile training for Ukrainian troops at Fort Sill, Oklahoma, is wrapping up soon, an Army spokesman said Tuesday.

Sixty-five Ukrainian soldiers have been training at Fort Sill since mid-January in an expedited training cycle on using the Patriots -- training that typically can last up to a year.

The Ukrainians will depart the Army post in the coming days for Europe, where they will receive additional training, before heading back to Ukraine "in the coming weeks," Col. Marty O’Donnell of U.S. Army Europe/Africa told ABC News.

"In Europe, the Ukrainians training here will meet up with Ukrainians training in Europe, and with U.S., German, and Dutch equipment donations to validate the systems and ensure interoperability," O'Donnell said.

-ABC News' Luis Martinez

The United States is going to speed up the manufacture and delivery of the 31 Abrams tanks President Joe Biden approved sending to Ukraine, a U.S. official confirmed Tuesday.

Instead of making new tanks from scratch, the Department of Defense will now refurbish the hulls of several older models that will be equipped with more modern equipment, according to the official.

The new delivery target date is fall 2023, the official said; previously the anticipated delivery time was believed to be mid-2024.

National Security Council spokesperson John Kirby hinted at the accelerated timeline on Tuesday.

"We're working on that," Kirby said on MSNBC. "There's some changes that you can make to the process to sort of speed that up."

-ABC News' Luis Martinez and Teresa Mettela

Japanese Prime Minister Fumio Kishida visited Ukraine on Tuesday for the first time since the start of Russia's invasion.

In Kyiv, Kishida laid a wreath at the memorial for fallen Ukrainian soldiers. In Bucha, where Ukrainian officials said more than 400 civilians were killed last year by Russian forces, he laid a wreath outside a church before observing a moment of silence and bowing.

"The world was astonished to see innocent civilians in Bucha killed one year ago," Kishida said. "I really feel great anger for all the atrocious acts."

-ABC News' Ellie Kaufman

Ukrainian forces destroyed Russian Kalibr-NK cruise missiles in a drone strike in Crimea as the weapons were being transported by rail, the Ukrainian Main Intelligence Directorate said on their official Telegram channel Monday.

Sergey Aksyonov, an adviser to the head of the Republic of Crimea, which Russia annexed in 2014, confirmed a drone attack on his official Telegram channel.

Debris from the aerial object damaged a household and a shop and one person was injured from the explosions, Aksyonov said.

-ABC News' Ellie Kaufman

Russia’s Wagner mercenary group said it will retreat from Bakhmut because of severe shortages in ammunition, according to Yevgeny Prigozhin, the group's leader. He said his forces would withdraw on May 10, blaming Russia’s defense ministry for the retreat.

Wagner has played a crucial role for months in the fighting for Bakhmut, sustaining huge casualties. The announcement and the suggestion of bitter infighting within Russia’s military forces signals division and disorganization just as Russia is bracing for a major Ukrainian counteroffensive.

Prigozhin said he was taking the decision in retaliation against Russia’s military leadership, which he accused of deliberately starving his troops of ammunition because they are jealous of Wagner’s success.

Prigozhin and Russia’s defense ministry have been in a one-sided public feud for months. Prigozhin claims it's now reached a breaking point, delivering a blistering attack on Russia's senior military command in the video announcing the withdrawal. He accused them of being "cowards" and of denying Russians a victory in Bakhmut because of their "petty envy."

Ukrainian military officials said they did not believe Wagner forces would retreat from Bakhmut, suggesting they believed his announcement was an attempt to excuse his failure to seize the city by May 9 as he pledged. A spokesman for Ukraine's eastern command, Sergiy Cherevatyi, said Wagner was running out of fighters, not ammunition.

-ABC News' Patrick Reevell