'Major' police investigation underway after explosion in Cologne, Germany

MAINZ, Germany — Police are investigating after an explosion rocked central Cologne in western Germany on Monday.

The explosion took place in the entrance way of the Vanity nightclub in the Hohenzollernring area, known as a main entertainment district of Cologne, at around 5.50 a.m. local time, a police spokesman told NBC News.

The police said that at least one person might have been slightly injured in the incident.

Several glass windows apparently burst in the explosion “and could have likely harmed more people, if the explosion had occurred at a later time,” the spokesman said.

Local authorities said in a post on X on Monday that a "major" police operation was underway as they urged residents to avoid the Hohenzollernring area.

The cause of the explosion was not immediately clear.

Police told NBC News that the area is under CCTV surveillance and that the footage will be part of the ongoing investigation.

This is a developing story. Please check back for updates.

Andy Eckardt reported from Mainz, and Chantal Da Silva from London.

This article was originally published on NBCNews.com