The meeting comes as Germany faces mounting pressure to provide Kyiv with its Leopard 2 tanks and allow the transfer of other Leopards from NATO member states.
Ukrainian President Volodymyr Zelenskyy said his government was expecting "strong decisions" from defence leaders of NATO and other countries meeting on Friday to discuss boosting Ukraine's ability to confront Russian forces with modern battle tanks.
The gathering at Ramstein Air Base in Germany Friday is meant to hammer out future military aid to Ukraine amid ongoing dissent over who will provide the armour that leaders in Kyiv say they desperately need to recapture territory from Russia.
While US representatives are there to discuss the latest massive package of aid Washington is sending — which includes Stryker armoured vehicles for the first time — broader hesitation over sending tanks to Ukraine has roiled the coalition.
Germany faces mounting pressure to supply Leopard 2s to Kyiv or at least clear the way for others — such as Poland — to deliver German-made Leopards from their own stock.
The US has also declined, at least so far, to provide M1 Abrams tanks, citing the extensive and complex maintenance and logistical challenges with the high-tech vehicle.
The US believes it would be more productive to send Leopards since many allies have them, and Ukrainian troops would only have to get trained on that one, versus needing far more training on the more difficult Abrams.
The UK announced last week that it would send Challenger 2 tanks, saying it was a natural progression of military aid to Ukraine.
Leopards are 'easier to maintain', Pentagon says
At a Pentagon briefing Thursday, spokeswoman Sabrina Singh said the Leopard and Challenger are not comparable to the Abrams because the Abrams is much harder to maintain and would not be a good fit.
"It's more of a sustainment issue. I mean, this is a tank that requires jet fuel, whereas the Leopard and the Challenger, it's a different engine."
The Leopard and Challenger are "a little bit easier to maintain," Singh said. "They can manoeuvre across large portions of territory before they need to refuel.
The maintenance and the high cost that it would take to maintain an Abrams — it just doesn't make sense to provide that to the Ukrainians at this moment."
The package of aid being sent by the US includes eight Avenger air defence systems, 350 Humvees, 53 Mine Resistant Ambush Protected (MRAP) vehicles, more than 100,000 rounds of artillery ammunition and rockets, and missiles for the High Mobility Artillery Rocket System, or HIMARS. It was announced Thursday by the Pentagon.
Germany's new defence minister, Boris Pistorius, who took office just an hour before he met with Austin on Thursday, is among those likely to attend the Ramstein meeting.
Referring to the tanks, he told ARD television he was "pretty sure we will get a decision on this in the coming days, but I can't yet tell you today how it will look."
It was unclear if the tank issue came up during his initial session with Austin. During brief comments before the meeting began, Austin said, "we'll renew our united commitment to support Ukraine's self-defense for the long haul," but did not mention any specific new equipment.
Nearly a year into the Russian invasion, Ukrainian President Volodymyr Zelenskyy has expressed frustration about not obtaining enough weaponry from the Western allies.
Speaking by video link on the sidelines of the World Economic Forum's annual meeting in Davos, Zelenskyy offered a veiled critique of major supporters such as Germany and the U.S. that have hesitated about sending tanks.
Bemoaning a "lack of specific weaponry," he said, through an interpreter, "There are times where we shouldn't hesitate or we shouldn't compare when someone says, 'I will give tanks if someone else will also share his tanks.'"
The influx of new weapons, tanks and armoured carriers comes as Ukraine faces intense combat in eastern Ukraine around the city of Bakhmut and the nearby salt mining town of Soledar. The battles are expected to intensify in the spring.