Gun battles have broken out in Pakistan's southern port city of Karachi between security forces and presumed supporters of the Muttahida Qaumi Movement, or MQM.

Several people were wounded in the clashes, which come days after three military courts began work in the city in a government drive to end chroniccrime and political violence there.

The MQM, which claims to represent Urdu-speakers, accuses the government of targetting its supporters in a security drive.

The Prime Minister, Nawaz Sharif, imposed federal rule on Karachi last month and brought in the army to combat the violence.