An "extensive" investigation found no evidence that the water supply at a German air force barracks was tampered with, Germany's Defense Ministry said on Friday.

It comes two days after the Wahn barracks near the western German city of Cologne in the state of North-Rhine Westphalia was sealed off.

What do we know about the probe into the Wahn barracks?

The probe into the Wahn barracks' water supply was launched on Wednesday after a hole was found in a fence near the base's waterworks.

Authorities reported having registered "abnormal water values" after examining the site and the facility was sealed off. Thousands of soldiers and civilians who work at the base were told not to drink tap water at the site.

The Defense Ministry said in a post on X, formerly Twitter, on Friday that "manipulation of the drinking water facility could not be confirmed after extensive investigations."

It added that the quality requirements for drinking water had been met while noting that "further investigations are ongoing."

The Wahn barracks serves the military part of Cologne/Bonn Airport.

North-Rhine Westphalia town partially lifts water warning

Meanwhile, local authorities in the town of Mechernich, which lies some 48 kilometers (29.8 miles) southwest of Cologne and is home to a Bundeswehr barracks, partially lifted a drinking water warning.

On Thursday evening, local officials said that a hole had been found in a fence on the grounds of a drinking water tank.

On Friday, authorities said that an analysis found no signs of chemical or biological contamination.

However, they advised that locals boil water before drinking it as a precaution while further test were carried out.

sdi/nm (dpa, AFP, AP, Reuters)