Pakistani Prime Minister Yousuf Raza Gilani has arrived in the country's southern port city of Karachi to try to quell unrest that has killed at least 85 people.

Monday's assassination of provincial lawmaker Raza Haider triggered four days of riots, with protesters opening fire and burning vehicles and shops.

Haider was a member of the Muttahida Quami Movement or MQM, which is part of the ruling political coalition in both Sindh province and the federal government.

The party, which largely represents the Urdu-speaking community, and the Awami National Party or ANP, which represents ethnic Pashtuns, have blamed each other for the violence.

Pakistan's Interior Minister Rehman Malik has said Taliban-linked militants looking to fuel political tensions were behind Haider's assassination.

Malik met with representatives from both the MQM and ANP on Friday.  Political leaders were due to meet with Prime Minister Gilani later in the day.

Some information for this report was provided by AFP.