At least eleven people have been killed and several injured in recent incidents of firing in different areas of Karachi over the past 24 hours, report said. Rangers and police have kicked off a search operation in restive parts of the metropolis, arresting more than 50 suspects and recovering illegal arms. In the latest incident of violence, a passenger bus was attacked by terrorists at Nagan Chowrangi area of the city, killing one and injuring five others. Police said unknown armed men riding motorbikes intercepted 2K bus near Board Office in Nazim Abad and sprayed bullets at the vehicle. A man died on the spot while several other suffered bullet wounds, an official said.