QUETTA: A bomb planted under a tea stall at a railway station in southwestern Pakistan has killed seven people, including a child, and wounded 18 others, police said Thursday.

The explosion Wednesday appeared to target the express train from the southwestern city of Quetta en route to Rawalpindi, the capital's twin city to the north, as it arrived at Sibi station, officials said.

“A total of seven people have been killed and 18 wounded,” senior police official Qazi Hussain Ahmad told AFP Thursday, updating an earlier toll of five dead and 15 injured.

Local administration official Shahid Saleem told AFP that the bomb exploded at around 11:30 pm (1830 GMT).

Authorities warned that with many of the injured in a serious condition the death toll could rise further, but that the casualties would have been greater had the train been fully on the platform at the time of the attack.

“The dead include a railway police constable and a child, aged six or seven,” Saleem said.

Sibi is a major railway junction about 400 miles (600 kilometres) southwest of Islamabad, in Pakistan's southwestern province of Balochistan. There was no immediate claim of responsibility for the attack.

Pakistani train travelers are usually among the country's least well-off, and often face laborious journeys in ageing carriages, along a network prone to serious delays.

Local official Qamar Maqsood said most of the victims had been standing on the platform when the bomb exploded.