Ammon News - Attackers wearing suicide bombs were sitting next to passengers taken hostage after militants took over a train in southwest Pakistan, sources said on Wednesday, complicating rescue efforts a day after the country's first such hijacking.

The separatist militants blew up a railway track and opened fire on the Jaffar Express on Tuesday as it travelled from Quetta, Balochistan's capital city, to Peshawar in Khyber Pakhtunkhwa province.

Pakistani forces have rescued 155 passengers, and the government said a security operation was under way to free dozens still held hostage, without specifying the exact number.

The Baloch Liberation Army (BLA), an ethnic armed group, claimed responsibility for the attack and threatened to start executing hostages unless Baloch political prisoners, activists, and missing persons it said had been abducted by the military were released within 48 hours.

BLA said on Tuesday it was holding 214 people hostage, and a security source told Reuters that there were 425 passengers on the train when it was attacked.

The number of militants involved in the attack was not clear. The security sources said on Wednesday that 27 had been killed so far. Reuters