KARACHI- Pakistan's biggest city was in lockdown for a second day today, with shops and markets closed and people staying home for fear of violence following the arrest in London.

Altaf Hussain, leader of the powerful Muttahida Qaumi Movement (MQM) party and wanted in Pakistan in relation to a murder case, was arrested in northwest London where he has lived in self-imposed exile since the early 1990s.

Karachi, a sprawling and violent port city of 18 million, is virtually controlled by Hussain's party, and reports of sporadic violence emerged as soon as news of his arrest reached the city.

Today, about 2,000 of his supporters rallied in the centre in support of Hussain but elsewhere the city was in lockdown, with markets and petrol stations closed and its usually chaotic and bustling streets empty of traffic.