Ukrainian troops will begin training on American M1 Abrams tanks in Germany in the next few weeks, US defence officials say, in what would be a major step in arming Kyiv in its efforts to seize back territory from Russia.

Defence secretary Lloyd J. Austin III was expected to make the announcement on Friday morning during a meeting with allies at Ramstein Air Base. Defence officials said that about 31 tanks were expected to arrive in Germany to kick off a training programme for Ukrainian troops that is expected to take 10 weeks. The tanks could reach the battlefields in Ukraine by autumn, said the officials, who spoke on the condition of anonymity to discuss security matters.

That is a vastly accelerated timetable from what the Pentagon had initially projected, and officials said it meant that Abrams tanks could get to Ukraine in time to play a part in the counteroffensive that Ukraine is expected to launch soon. The counter-offensive is expected to begin in weeks, and the Abrams tanks could arrive in time to help Ukrainian troops hold reclaimed territory, one of the officials said.

Defence officials had initially said that the M1 Abrams tanks would not arrive in Ukraine until next year. But since January, when the Biden administration announced that it would send the tanks, senior defence officials have said that they wanted to speed up the timeline.

Austin, during remarks on Friday at US-led talks with top defence officials from more than 40 nations, a collective known as the Ukraine Contact Group, said that the continued deliveries of weapons systems and ammunition and tanks to Kyiv “underscore just how badly the Kremlin miscalculated.”

“Putin thought that he could easily topple Kyiv’s democratically elected government,” Austin told the defence ministers assembled in a cavernous room in the officers’ club at Ramstein, referring to President Vladimir V. Putin of Russia. “He thought that the wider world would let him get away with it.”

Austin’s trip to Europe — he arrived in Germany on Thursday — has been overshadowed by the investigation of the leak of hundreds of top-secret national security documents.

“I know many of you have been following the reports of unauthorised disclosure of sensitive and classified US material,” Austin said. “I take this issue very seriously.” He praised the Ukraine Contact Group for its “commitment to reject efforts to divide us”.