Poland has formally asked Germany for permission to export a batch of Leopard 2 battle tanks to Ukraine, in a move that increases pressure on Berlin.
The German government told the BBC it had received an export request for 14 German-made tanks on Tuesday.
But she insisted that the final decision was up to Chancellor Olaf Scholz.
Ukraine sees tanks as necessary to break through Russian lines and overcome an expected attack.
Germany remains reluctant to send those tanks, or to allow other countries to do the same, because one of its fears is that any sudden move could lead to further escalation of the conflict with Russia.
German Defense Minister Boris Pistorius said on Tuesday that Berlin had given allied countries the green light to train Ukrainians to use Leopard 2 tanks, but had not committed to sending its tanks.
He added that a decision on the supply of tanks will be taken soon. The Army Chief of Staff added that any decision that would be taken would be at the political level.
"We encourage our partners if they want to, if they have the opportunity, to start training Ukrainian forces on these Leopard tanks," Pistorius said at a press conference with NATO Secretary General Jens Stoltenberg.
And the Allied countries were frustrated by what they see as Germany's reluctance to send these armored vehicles in recent days.
Speaking on Tuesday, Polish Defense Minister Mariusz Blaszczak said he had appealed to Germany "to join the coalition of countries that support Ukraine with Leopard 2 tanks."
He added: "This is our common cause, because the security of all Europe is at stake!"
Lithuanian President Gitanas Nauseda said on Tuesday that Poland is determined to send its tanks to Ukraine, after meeting with Polish President Andrzej Duda.
"It is unfortunate that sometimes there is a totally unnecessary delay, as we could have taken decisions sooner. The Polish side is very eager to provide such support," Noseda said.
But Pistorius defended German Chancellor Olaf Scholz in the face of criticism that he was dragging his feet.
"Taking the initiative does not mean moving forward blindly. If the decision takes another day or two, this is the way it is," he said.