Islamabad: The port city of Karachi was tense on Friday following a new wave of violence and arson caused by the assassination of a political leader, media reports said.

Nearly a dozen people were killed in incidents of violence in the capital of Sindh province that followed the murder of an Awami National Party (ANP) activist Obaidullah Yousufzai on Thursday by gunmen who sprayed his car with bullets.

More than ten vehicles were also set on fire in different parts of the largest Pakistani city and the country's industrial and commercial hub.

Paramilitary soldiers and police intensified patrolling in the troubled areas of the provincial metropolis, which helped control the situation.

ANP, a partner in the Sindh ruling coalition led by the Pakistan People's Party, declared three-day mourning for slain Yousufzai, whose body was taken to Peshawar, capital of northwestern Khyber Pakthunkhwa province, the base of the party representing mainly the Pashtu-speaking people.

A similar wave of violence had swept Karachi after August 2 assassination of provincial legislator Raza Haider of Mutahidda Qaumi Movement, also part of the governing coalition. Close to a score of people lost their lives in that eruption.

Karachi police have reportedly arrested four suspects until now in connection with the slaying of the legislator.