An explosion went off near a police car in in the troubled southern Russian region of Dagestan. There were no injuries in the incident in the town of Khasavyurt near the border with Chechnya.
Near-daily attacks on police and authorities in Dagestan have raised fears that violence is spreading from war-torn Chechnya to other Caucasus regions. Some of the violence is believed to be tied to criminal gangs and disputes between local clans.
President Vladimir Putin visited Dagestan last month in a sign of Kremlin concern for the region's stability.
Also Monday, regional authorities said police found a weapons cache containing two grenade launchers and ammunition on the outskirts of Buinaksk, south of the capital of Makhachkala, the AP reports.
There are several versions of the recent assassination of the most prominent Iranian nuclear scientist and high-ranking officer of the Islamic Revolutionary Guard Corps, Mohsen Fakhrizadeh