ISLAMABAD — Armed militants in Pakistan's Balochistan region have attacked a train carrying hundreds of passengers and taken a number of hostages, military sources said.

The Baloch Liberation Army (BLA) fired at the Jaffar Express Train as it traveled from Quetta to Peshawar.

A statement from the separatist group said it had bombed the track before storming the train in remote Sibi district. It claimed the train was under its control.

Pakistani police told local reporters at least three people, including the train driver, had been injured. Security forces have been sent to the scene, as well as helicopters to try to rescue hostages, police told the BBC.

There were reports of "intense firing" at the train, a Balochistan government spokesman told local newspaper Dawn. A senior police official said it "remains stuck just before a tunnel surrounded by mountains", AFP news agency reports.

The Baloch Liberation Army has warned of "severe consequences" if an attempt is made to rescue those it is holding.

It has waged a decades-long insurgency to gain independence and has launched numerous deadly attacks, often targeting police stations, railway lines and highways. The Pakistani authorities — as well as several Western countries, including the UK and US — have designated the BLA as a terrorist organization.

Quetta's railway controller Muhammad Kashif told the BBC that 400-450 passengers had been booked on the train. Officials have not confirmed how many they think have been taken hostage.

Railway officials in Quetta, quoting paramilitary sources, told the BBC that women and children had disembarked from the train and were walking towards the city of Sibi. They did not have an exact number.

Meanwhile, families of passengers are trying to get information from the counter at Quetta railway station.

The son of one passenger, Muhammad Ashraf, who left Quetta for Lahore on Tuesday morning, told BBC Urdu he had not been able to contact his father. Officials say they are yet to communicate with anyone on the train.

The area has no internet and mobile network coverage, officials told the BBC.

Balochistan is Pakistan's largest province and the richest in terms of natural resources, but it is the least developed.

A decades-long insurgency in Balochistan by separatist militant groups has led to frequent attacks against the government, army and Chinese interests in the region, pressing demands for a share in mineral-rich resources.

The BLA seeks independence for Balochistan. It is the biggest of several ethnic insurgent groups that have battled the South Asian nation’s government for decades, saying it unfairly exploits Balochistan’s rich gas and mineral resources. — Agencies