BERLIN (AP) — All of Germany's six submarines are out of action, and the country's defense minister isn't happy about it.

The Kieler Nachrichten newspaper reports that four U-boats are being serviced in boatyards while two others are waiting for a berth.

Asked how Defense Minister Ursula von der Leyen views the temporary loss of the underwater fleet, her spokesman said Friday that "this is obviously not a good situation."

Jens Flosdorff told reporters in Berlin that "we would hope the mission readiness was higher, but sometimes with technology the devil is in the detail."

U-boats became the pride of the German navy in World War I, when the Kaiser's submarines dealt several heavy blows to the British navy.