BERLIN - The main train station in the western German city of Cologne has been closed due to an ongoing police operation, state-owned rail operator Deutsche Bahn said on Monday after police said they were investigating a suspected hostage-taking.

"A police operation is delaying rail traffic, the main station in Cologne is closed," Deutsche Bahn said on Twitter, adding it did not know how long the police operation would last.

(Reporting by Maria Sheahan Editing by Michelle Martin) ((maria.sheahan@thomsonreuters.com; +49 30 2888 5169; Reuters Messaging: maria.sheahan.thomsonreuters.com@reuters.net))