More than 20,000 people have rallied in Pakistan's largest city, Karachi, to protest cartoons of the Prophet Muhammad.
Shouting anti-American and anti-European slogans, the demonstrators marched through the city on Sunday to denounce the cartoons, first published in Denmark.
Earlier, in the eastern city of Lahore, police fired teargas to put a stop to a rally organized by the six-party Muttahida Majlis-e-Amal alliance. Police arrested the head of the alliance, Qazi Hussain Ahmed, and dozens of others including cricketer-turned-politician Imran Khan.
Protests have been banned in Lahore, where two people died in earlier unrest.
Radical Islamic leaders said they would defy the ban and stage more protests.
Demonstrations have been scheduled for Friday, the day before President Bush is due to visit Islamabad on his South Asia trip.
Some information for this report was provided by AFP, AP and Reuters.