QUETTA, Pakistan (AP) -- A suicide bomber blew himself up at a train station in restive southwestern Pakistan on Saturday, killing at least 24 people, including soldiers and railways staff, and wounding about 50 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 the restive Balochistan province, according to Hamza Shafqaat, a senior government administrator.

Police said about a dozen soldiers and six railway employees were among the dead.

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.

TV footage showed the steel structure of the platform's roof blown apart and a tea stall destroyed as luggage littered the place.

Ayesha Faiz, a Quetta police official, said some of the critically wounded passengers died at a hospital, raising the deaths.

Shahid Rind, a government spokesperson said all the wounded were transported to hospitals for treatment.

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."

The attack 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 Balochistan, killing nine people including five nearby children.

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.

The oil- and mineral-rich Balochistan is Pakistan's largest but also least populated province. It is also 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.

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