Pakistani security forces stormed a train on Wednesday that had been hijacked by separatist militants, killing all 33 attackers and ending a day-long standoff involving hundreds of hostages, the military said.

Separatist Baloch militants on Tuesday blew up the railway track and hurled rockets at the Jaffar Express when it was on its way to Peshawar in Khyber Pakhtunkhwa province from Balochistan’s capital of Quetta, carrying 440 people.

The military said 21 hostages and four security troops were killed over the course of the standoff.

“Today we freed a large number of people, including women and children … The final operation was carried out with great care,” military spokesperson Ahmed Sharif Chaudhry said, adding that no civilians were killed in the final stage of the operation.

Before the army announcement, the Baloch Liberation Army, which claimed the attack, said it had killed 50 passengers on Wednesday evening.

It had said on Tuesday that it was holding 214 people, mostly security personnel. It had threatened to start executing hostages unless authorities met its 48-hour deadline for the release of Baloch political prisoners, activists, and missing people it says had been abducted by the military.

The BLA is the largest of several ethnic armed groups battling the government in Balochistan, which borders Afghanistan and Iran.

The militants have in recent months stepped up their activities using new tactics to inflict high death and injury tolls and target Pakistan’s military.

Baloch militant groups say they have been fighting for a larger share in the regional wealth of mines and minerals denied by the central government.

Junior Interior Minister Talal Chaudhry told Geo television earlier on Wednesday that militants were wearing suicide vests as they sat among the passengers held hostage, complicating the rescue attempt.

He said 70-80 attackers had hijacked the train.

The military sent in hundreds of troops and also deployed the airforce and special forces to tackle the militants, Chaudhry said.

In the final phase of the operation, he said special forces first took out the suicide bombers before troops went from carriage to carriage to kill the rest of the militants. He did not give a number of those rescued in this phase of the operation and it was not immediately clear how or to where the passengers would be evacuated.

The train driver and several others had already been killed, officials said earlier, before the army statement.

Government officials had said earlier, also before the army statement, that 190 of those on board had already been rescued, with more than 50 taken to Quetta to be reunited with their loved ones.

Muhammad Ashraf, 75, who was travelling on the train, said he heard a loud explosion in the mountainous area, which shook all the carriages.

“We lay on the floor once heavy firing started. Shortly after, armed men entered the train and checked our identities,” he said in Quetta.

A security official had told Reuters that the armed men were looking for soldiers and security personnel.

A woman, who said her son was among the passengers still waiting to be freed, confronted provincial minister Mir Zahoor Buledi. “Why didn’t you stop the trains if they were not safe?” she said.

Buledi told reporters the government was working to beef up security in the region.