ISLAMABAD, Nov. 16 (Xinhua) -- At least two people were killed and 10 others injured in a bomb blast in Pakistan's southern port city of Karachi late Friday, local media and police officials said.

Irfan Bahadur, senior superintendent police, said that the blast took place under a bridge in the Quaidabad area of Karachi, the provincial capital of southern Sindh province.

He added that the nature of the blast was not known, and police had launched an investigation in the incident.

The injured were shifted to a hospital in the city, where several of them were said to be in critical condition.

Security personnel cordoned off the area after the blast and launched a search operation.

No group or individual has claimed responsibility for the attack.

Chief Minister of Sindh Syed Murad Ali Shah had directed hospital authorities to provide the best medical treatment to the injured people.