Karachi: Still reeling from a spate of gang wars, Pakistan's commercial hub has now been hit by sectarian violence with at least five people killed in clash between two religious groups, police said on Monday.

The clash occurred on Sunday between banned Sunni extremist group 'Sipah-e-Sahaba' and 'Sunni Tehrik' at New Karachi area.

The police said that unidentified armed men shot dead an activist of Sunni Tehrik, which provoked the group and its supporters launched a counter attack on the rival Sipah-e-Sahaba group

Both sides exchanged firing for two hours, which resulted into the death of five people. The firing forced the residents to stay indoors.

Later, paramilitary force and police launched a search operation against the rival groups and detained several of their members.

Police said that three more people were killed in the overnight firing incidents in Karachi.

Fresh violence occurred at a time when the Supreme Court resume hearing of the lawlessness in Karachi.

The police chief of Sindh province, of which Karachi is the capital, told the apex court last week that 306 people were killed in ethnic and sectarian violence between July 24 to August 24.

The Supreme Court had criticised the role of the police and other law enforcement agencies for their failure to control target killings.

Meanwhile, Pakistani President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani are trying to woo the powerful ethnic group the Mutahida Qaumi Movement (MQM) to rejoin the government.

The MQM quit the federal and Sindh cabinets over differences with the ruling Pakistan's Peoples Party, the decision, according to analysts, is of the reasons of the violence.

President Zardari and Prime Minister Gilani called the MQM self-exiled leader Altaf Hussain in London on phone and reportedly asked him to bring his ministers back to the cabinet.

Zardari has assigned federal minister Khurshid Shah to meet senior MQM leadership in Karachi later on Monday and finalise agreement with them, reports said.