Meanwhile, thousands continued to take part in street protests and Denmark temporarily closed its embassy and advised its citizens to leave the country.
Police confined the former leader of an Islamic militant group to his home to prevent him from addressing supporters over the cartoons, amid fears he could incite violence, after riots this week killed five people.
A leading media watchdog yesterday urged the release of six journalists held in Algeria and Yemen for reprinting caricatures of the Prophet Mohammed that have provoked violent protests in the Muslim world.
“Whatever one thinks of the cartoons or whether they should be published, it is absolutely unjustified to jail or prosecute journalists, threaten them with death or shut down newspapers for this reason,” Reporters Without Borders said in a statement.
In addition to the journalists arrested in Algeria and Yemen, a further 12 reporters in five countries are being prosecuted for printing the cartoons, the Paris-based group said. It appealed for all the charges to be dropped.
The group earlier said a Syrian writer had also been arrested over the cartoons, but later said he was being held for other reasons.
In Pakistan, security forces were out in strength, particularly around government offices and Western businesses, as Muslims streamed onto the streets after Friday prayers. More than 200 people were detained, but most gatherings were peaceful.
In neighbouring India, police used batons and tear gas to disperse thousands of angry worshippers who rioted in the southern city of Hyderabad. They burned Danish flags, pelted police with stones, and looted shops. Hundreds more protested in Bangladesh.
In the north-western Pakistan city of Peshawar, prayer leader Mohammed Yousaf Qureshi announced the bounty for killing a cartoonist to about 1,000 people outside the Mohabat Khan mosque.
Mr Qureshi said the mosque and his religious school would give $25,000 and a car, while a local jewellers’ association would give another $1m. No representative of the association was available to confirm it had made the offer.
“This is a unanimous decision by all imams (prayer leaders) of Islam that whoever insults the prophet deserves to be killed and whoever will take this insulting man to his end, will get this prize,” Mr Qureshi said.
The cleric did not name any cartoonist in his announcement and did not appear to be aware 12 people had drawn the pictures.
A Danish newspaper, Jyllands-Posten, first printed the prophet pictures by 12 cartoonists in September.
The newspaper has since apologised to Muslims for the cartoons, one of them showing Mohammed wearing a bomb-shaped turban with a burning fuse.
Other Western newspapers, mostly in Europe, have reprinted the pictures, asserting their news value and the right to freedom of expression.
In Islamabad, former US President Bill Clinton criticised the cartoons but said Muslims wasted an opportunity to build ties with the West by the violent protests.
“I can tell you, most people in the US deeply respect Islam and most people in Europe do,” he said on a visit to an HIV-AIDS project by his foundation.
Unrest over the cartoons has spiralled in Pakistan, although it has ebbed in the rest of Asia and in the Middle East. Big riots in Lahore and Peshawar this week caused millions in damage, as hundreds of vehicles were burned and protesters targeted foreign businesses.
Intelligence officials have said scores of members of radical and militant Islamic groups joined the protests in Lahore and had incited violence to undermine President Pervez Musharraf’s government.