(CNN) -- An explosion near a provincial government motorcade rocked a residential area of Pakistan's most populous city on Friday, killing at least four people and injuring 30 others, a provincial spokesman said.
The blast happened in Karachi as three provincial government cars were moving along a road, said Sharjeel Memon, information minister for Sindh province.
The vehicles were badly damaged, Memon said. One car belonged to the province's cultural secretary, though the secretary wasn't in the vehicle, Memon said.
It wasn't immediately clear whether any of the dead or injured had been in the vehicles.
Memon didn't give details on what caused the blast, though he described it as an attack on the vehicles.