Pakistani authorities say a bomb has exploded at a railway station in the southwestern province of Baluchistan, killing at least five people and wounding more than 20 others.

The attack happened late Wednesday as a train pulled into the station in Sibi city. There were no immediate claims of responsibility and no word of any arrests. Baluchistan has experienced years of violence by separatists who demand a greater share of the Pakistani region's natural resources. Taliban militants also have been active in the province.

Hours before Wednesday's bombing, Pakistani Interior Ministry chief Rehman Malik said his government recently handed evidence to Indian authorities of contacts between Baloch separatists and handlers in India.

New Delhi denies Pakistani charges of Indian involvement in Baluchistan.