NEW YORK (AP) — High-end hotel chain Mandarin Oriental said Thursday that the credit card systems at some of its hotels in the U.S. and Europe were hacked.

The company, however, did not specify which of its hotels were affected. It also did not give details on the extent of the hack or how many customers reported fraudulent charges on their credit cards as a result.

Mandarin Oriental operates about 30 hotels in cities across the world including Paris, London, Geneva, New York, Miami, San Francisco, Las Vegas as well as Shanghai, Hong Kong and Macau.

The company said it has removed the bad software from its systems and that it is still investigating the breach. On Wednesday, it said it was looking into a potential breach.

Several companies have been the target of cyberattacks in the last year, including retailer Home Depot and bank JPMorgan Chase.

Mandarin Oriental is a unit of conglomerate Jardine Matheson Group. The hotel group is operated from Hong Kong.