Germany's government named Boris Pistorius as the new defense minister on Tuesday.

Christine Lambrecht resigned as defense minister Monday before a conference at the U.S. military base in Ramstein on Western plans to give Kyiv more weapons.

So far, Germany has been cautious in approving the sending of Leopard heavy tanks because of fears that such a move could be perceived as an escalation of the war. Other countries with such tanks also need Berlin's approval before they can be transferred to another country.

Pistorius, 62, who completed his military service, has been interior minister of Lower Saxony since 2013. He ran for the leadership of the Social Democratic Party (SPD) in 2019 and is known for his tough stance on security issues. He gained national credibility during the 2015 migration crisis when he supported restrictive migrant policies.

"There are important decisions to be made in the short term, in particular the urgent question of how we continue to support Ukraine in its right to self-defence," Economy Minister Robert Habeck, said in a statement.

"Germany bears a responsibility here and has major tasks to accomplish," he said.

Pistorius was in a relationship with Doris Schroeder-Kopf, the former wife of former Chancellor Gerhard Schroeder. He was also a member of the Bundesrat's German-Russian friendship group in the upper house of parliament until its dissolution in April.