Armed militants took over 450 train passengers hostage and injured the train driver during an attack on Tuesday in Pakistan's volatile southwestern Balochistan province, according to officials.

The Baloch Liberation Army (BLA), which claimed responsibility for the assault, stated that gunmen detonated explosives on the railway track and took control of the train in the isolated Sibi district.

"Over 450 passengers onboard are being held hostage by gunmen," Muhammad Kashif, a senior railway government official in Quetta, the capital of the province, told AFP.

A senior police official from the area near Sibi, who requested to remain unnamed due to media restrictions, stated that "the train is stranded just before a tunnel, surrounded by mountains."

The location where the train is halted is a mountainous region, providing militants with opportunities to hide and plan attacks.

According to another senior police official, an emergency has been declared in the nearby hospitals.

In a statement, the BLA took responsibility for the attack, claiming that six military personnel were killed during the incident.

The group stated that they had taken hostages from the train, including security forces, although the exact number of captives remains unclear.

"During this operation, BLA fighters have released women, children, and Baloch passengers, ensuring that all remaining hostages are serving personnel of the occupying forces," the group said in their statement.