BERLIN—German police say someone broke into a hotel room that was used as an office of the chancellor's conservative party while Angela Merkel was holding talks in the same building.

Police spokeswoman Antje Roeper said Sunday nothing appears to have been stolen and no explosives were found.

She says Merkel and other party leaders were holding an internal two-day conference near the town of Neuruppin north of Berlin when the incident was discovered Sept. 17. Merkel, the Christian Democrats' chairwoman, was in a meeting on a different floor of the boutique hotel.

Roeper says the room was used as an office to facilitate the conference's organization. No motive has been established as police continue to investigate.

A spokesman for Merkel's party declined to comment on the incident.