Germany has said it would not object if Poland decides to send Leopard 2 battle tanks to Ukraine.
French TV channel LCI posted clips from an interview with foreign minister Annalena Baerbock on Sunday, in which she said her government has not received a formal request for approval from Warsaw, but added "if we were asked, we would not stand in the way".
The Ukrainian government has said it needs advanced tanks to continue its defence against Russia's invasion and war.
Berlin has hesitated in signing off on supplying the German-made Leopards, but agreed on Friday to review its stocks.
Polish prime minister Mateusz Morawiecki criticised Germany's reluctance, saying that if the country did not consent to transferring Leopard tanks to Ukraine, his country was prepared to build a "smaller coalition" of countries that would send theirs anyway.
On Sunday, the speaker of the lower house of Russia's parliament, State Duma chairman Vyacheslav Volodin, said: "Supplies of offensive weapons to the Kyiv regime would lead to a global catastrophe.
"If Washington and NATO supply weapons that would be used for striking peaceful cities and making attempts to seize our territory as they threaten to do, it would trigger a retaliation with more powerful weapons."
Germany is one of the main donors of weapons to Ukraine, and it ordered a review of its Leopard 2 stocks in preparation for a possible green light.
However, the government in Berlin has shown caution at each step of increasing its commitments to Ukraine.
French President Emmanuel Macron, meanwhile, has said he does not rule out sending Leclerc battle tanks to Ukraine and had asked his defence minister to "work on" the idea.
UK Foreign Secretary James Cleverly said he would like "nothing more" than to see Ukrainians armed with the German-made tanks.
So far among the NATO allies, only the UK has agreed to send tanks to Ukraine, in the form of 14 British Army Challenger 2s.
There had been hopes that Germany would authorise the release of its battle tanks, which are potentially available in far greater numbers.
But at the conclusion of a pledging conference on Friday at the US airbase in Ramstein, Germany, US Defence Secretary Lloyd Austin said: "I don't have any announcements to make on M1s (US Abrams tanks), and you heard the German minister of defence say that they've not made a decision on Leopards."