BERLIN (AP) — Defense officials said Monday that Germany is readying decades-old armored personnel carriers for a key NATO unit after the modern vehicles that should have been deployed suffered a mass breakdown.

Germany is scheduled to take the rotating lead of NATO's Very High Readiness Joint Task Force, or VJTF, on Jan. 1.

The German army's 37th Panzergrenadier Brigade had originally earmarked dozens of modern Puma APCs for the force, but during a recent military exercise all 18 Pumas deployed suffered technical failures.

A Defense Ministry spokesman said the ailing Pumas will now be replaced with much older Marder vehicles.

“We have made commitments toward NATO that we will fulfill with those APCs," the spokesman, David Helmbold, told reporters in Berlin.

Defense Minister Christine Lambrecht called the Puma breakdowns "a harsh setback” and ordered a halt to additional purchases of them.

“Our troops need to be able to rely on weapons systems being robust and stable even in combat,” she added.