QUETTA, Pakistan – A suicide bomber blew himself up at a railway station in Pakistan’s restive southwest on Saturday, killing at least 26 people, including soldiers and railway staff, and wounding about 62 others, some critically, officials said.

The attack occurred as nearly 100 passengers were waiting for a train to travel to the garrison city of Rawalpindi from Quetta, the capital of Balochistan province, according to Hamza Shafqaat, a senior government administrator.

Asked about a security breach that led to the bombing, Shafqaat told reporters that “it’s usually very difficult to stop such suicide attacks.”

However, Shahid Nawaz, who is in charge of security at Quetta’s railway station, insisted that there was no breach as the attacker was disguised as a passenger and blew himself up among people in the station.

TV footage showed the steel structure of the platform’s roof crushed and a tea stall destroyed. Luggage was scattered everywhere. Most of the victims were taken to a state hospital, and some to a military one.

Wasim Baig, a spokesman for the health department and the police, said more than a dozen soldiers and six railway employees were among the dead at the station, where a pass gate had been set up to check if anyone was carrying explosives. However, there are several other entrances to the station without such security.

A separatist group, the Balochistan Liberation Army, claimed responsibility for the attack in a statement, saying a suicide bomber targeted troops present at the station. The outlawed BLA has long waged an insurgency seeking independence from Islamabad.

A senior superintendent of police operations, Muhammad Baloch, said the separatists frequently attacked soft targets.

“When their men are arrested, they also attack in revenge. We all have to fight this war. We are resilient. Our teams are here trying to save as many lives as possible.”

Police said some of the seriously injured passengers died in hospital, raising the death toll.

Prime Minister Shehbaz Sharif denounced the attack in a statement, saying those who orchestrated the attack “will pay a very heavy price for it,” adding that security forces were determined to eliminate the “threat of terrorism.”

Afghanistan’s Foreign Ministry also condemned the bombing and expressed condolences to the families of the victims, as did the Russian Embassy in Islamabad.

Saturday’s attack came just over a week after a powerful bomb attached to a motorcycle exploded near a vehicle carrying police officers assigned to protect polio workers in the province, killing nine people, including five children who were bystanders.

In August, the BLA carried out several coordinated attacks on passenger buses, police and security forces in Balochistan, killing more than 50 people, mostly civilians.

Balochistan, rich in oil and minerals, is the largest but also the least populated province of Pakistan. It is a center for the country’s Baloch ethnic minority whose members say they face discrimination and exploitation by the central government. Along with separatist groups, Islamic militants also operate in the province.

The BLA mainly targets security forces and foreigners, particularly Chinese nationals who are in Pakistan as part of Beijing’s multibillion-dollar Belt and Road Initiative, which is working on major infrastructure projects. The group often calls for a halt to all Chinese-funded projects and for workers to leave Pakistan to avoid further attacks.

Last month, the BLA claimed responsibility for a suicide bombing targeting a convoy of Chinese nationals outside Karachi airport, killing two people. Beijing has asked Pakistan to ensure the safety of its citizens working in Balochistan and other parts of the country.