Berlin police are trying to determine the source of 200 rounds of ammunition found in an underground parking lot in the German capital.

Officers were called after a tenant of the building in the western district of Charlottenburg discovered a bag containing the bullets late Sunday.

German news agency dpa reports that police searched the surrounding area with sniffer dogs but found no further ammunition.

Germany is nearing the first anniversary of a terror attack in Berlin in which 12 people were killed by a Tunisian man who drove a stolen truck into a crowded Christmas market. The attack was later claimed by the Islamic State group.

Security officials have said Germany could be the target of further attacks but there are no indications anything specific is planned.