On Monday, German Defense Minister Christine Lambrecht announced her resignation from the administration of Chancellor Olaf Scholz, the climax of rising skepticism about her capacity to rebuild Germany’s armed forces in the context of the Ukraine conflict.

Her choice was a setback for Scholz at a time when Germany is being pressed to authorize a boost in foreign military assistance to Kiev and its defense capabilities have come under scrutiny after four Puma infantry tanks were rendered inoperable during a recent military exercise.

The pressure to find a successor is mounting also because U.S. Secretary of Defense Lloyd Austin is expected in Berlin on Thursday and will attend a conference on Friday at the U.S. military base in Ramstein, in the state of Rhineland-Palatinate, to discuss further support for Ukraine, including whether to send German-built battle tanks.

Lambrecht asked Scholz to dismiss her, as formally required, and he has approved, a spokesperson for the Social Democratic (SPD)-led coalition government said.

During a visit to arms manufacturer Hensoldt, Scholz thanked Lambrecht for her service and said he would act fast to replace her. “I have a clear idea and it will be known very quickly for everyone how this should proceed,” he told reporters.

Citing government sources, the Frankfurter Allgemeine Zeitung newspaper said a successor would be announced on Tuesday.

Among the candidates mooted by German media are Parliamentary Commissioner for the Armed Forces Eva Hoegl, junior defense minister Siemtje Moeller, SPD party chief Lars Klingbeil and Labour Minister Hubertus Heil.

Scholz has promised to staff his cabinet with equal numbers of men and women. If a man should succeed Lambrecht, this could result in further reshuffling.