Germany will allow German-made tanks to be sent to Ukraine to help its defense against Russia if the United States agrees to send its own tanks, a German government source told Reuters.
German Chancellor Olaf Scholz has stressed the stipulation several times in recent days behind closed doors, the person said, speaking on condition of anonymity.
Western allies will meet at a U.S. air base in Germany on Friday to discuss offering more weapons for Ukraine.
Attention is focused in particular on Germany, which has veto power over any decision to send its Leopard tanks, fielded by NATO-allied armies across Europe and widely seen as the most suitable for Ukraine.
Polish President Andrzej Duda told attendees at an economic forum in Davos, Switzerland, on Wednesday that he was afraid Russia was preparing a new offensive in Ukraine within months and it was therefore crucial to provide additional support to the Kyiv government with modern tanks and missiles.
Poland and Finland have said they will send Leopard tanks if Germany approves them.
Berlin says a decision will be the first item on the agenda of Boris Pistorius, Germany's new defense minister.
Pistorius will host U.S. Defense Secretary Lloyd Austin on Thursday.
The United States has committed roughly $24 billion to help Ukraine defend itself against Russian forces.
U.S. officials, speaking on the condition of anonymity, said President Joe Biden's administration is next expected to approve Stryker armored vehicles for Ukraine but is not poised to send its own tanks, including the M1 Abrams.
This week, London turned up the pressure on Berlin by becoming the first Western country to send Western tanks, pledging a squadron of its Challengers, but the Leopards are seen as the best choice to supply Ukraine with a large-scale tank force.
The Wall Street Journal, citing senior German officials, first reported Berlin's condition on tanks earlier on Wednesday. The publications Sueddeutsche Zeitung and Bild had similar reports.