Karachi bomb kills at least six people, wounds over 40

A bomb devastated a bus full of passengers in Karachi, Pakistan on Saturday, killing six people and wounding 48, police and a hospital official said, according to Reuters.

The attack occurred outside Karachi Cantonment Station, the city's main rail station. It's unclear if the bomb was on the bus or was detonated nearby. Imran Shaukhat, a spokesman for the Sindh police, told News Pakistan the cause of the explosion was unknown.

Al Jazeera says it's "unclear if Saturday’s blast was caused by a bomb or a gas cylinder exploding."

Victims were rushed to Jinnah Hospital, where Dr. Seemi Jamali told Reuters, eight wounded victims were in critical condition.

No group has claimed responsibility, though Pakistan's largest city has suffered many terrorist attacks over the past years as sectarian violence continues to plague the city.

Also on Saturday, unidentified gunman assaulted police officers in the city of Quetta, killing at least three people, the Associated Press reported. As with the bus bombing, no group claimed responsibility, but officials blame insurgents who committed similar attacks in the past.