At least 23 people were killed and 22 others wounded in firing in the southern port city of Karachi in Pakistan on Wednesday, local media reported.

A Pakistani motorcyclist rides past a burning passenger mini bus on a street in Karachi.[Xinhuanet.com]

The violence took place in different parts of Karachi when unidentified gunmen opened fire and set ablaze vehicles, the private Geo TV channel said.

Police and rescue sources said that over a dozen police and security personnel were also injured in the crossfire between two groups in various areas.

Pakistani police have arrested 21 suspected gunmen during a search operation and started investigation into the violence.

A vehicle burns after clashes in the southern city of Karachi April 29, 2009.[Xinhuanet.com]