MAKHACHKALA, Russia —  An explosion went off Friday night near a police building in the restive Dagestan (search) region adjacent to Chechnya (search), and a police official said two people were killed.

The blast occurred near the city police headquarters in Khasavyurt (search), regional Interior Ministry duty officer Abakar Ismailov said. There were conflicting reports about the cause, and Ismailov said it wasn't immediately clear.

The ITAR-Tass news agency quoted police as saying the explosion was caused by a gas canister and took place at a cultural center near the police building.

The Interfax news agency cited city officials who also blamed a gas canister, which they said was in a cafe. But emergency officials said the blast was apparently caused by an explosive device.

Both news agencies reported the victims were a woman and a small child and that part of the cultural center collapsed following the explosion.

Khasavyurt has been tense amid a conflict between its mayor and Dagestan's top official.

Dagestan has been plagued by shootings, bombings and other violence, some spilling over from neighboring Chechnya. Some violence is committed by local criminal gangs or is connected to power struggles in the mostly Muslim region.

Several attacks in and around Chechnya in recent years have targeted police facilities, and Russia is on edge after two planes crashed nearly simultaneously on Tuesday — at least one as a result of terrorism, officials said Friday.