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

The attack happened when 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.

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

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

TV footage showed the steel structure of the platform’s roof blown apart and a destroyed tea stall. Luggage was strewn everywhere. Most of the victims were taken to a state-owned hospital and some to a military one.

Wasim Baig, a spokesman for the health department and police said over a dozen soldiers and six railway employees were among the dead at the station, where a walk-through gate has been installed to check whether anyone is carrying explosives. Still, there are multiple other entrances to the station without such security.

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

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

“When their people are arrested, they also attack in retaliation. We all have to fight this war. We are resilient. Our teams are here and trying to save as many lives as we can.”

Police said some of the critically wounded passengers had died in the hospital, raising the death toll.

Prime Minister Shehbaz Sharif denounced the bombing 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 menace of terrorism.”

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

Saturday’s assault came a little 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 nearby.

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

Oil- and mineral-rich Balochistan is Pakistan’s largest but also least populated province. It is a hub for the country’s ethnic Baloch 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 mostly targets security forces and foreigners, especially 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 demands the halt of all Chinese-funded projects and for workers to leave Pakistan to avoid further attacks.

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