More than 2,000 supporters of a coalition of radical Muslim groups rallied Friday in the Pakistani capital to condemn a crackdown on Islamic militants that has netted more than 200 suspects.

Chanting "God is great" and "Down with America," the protesters -- mostly Islamic students and members of a coalition known as Mutahida Majlis-e-Amal, or United Action Forum -- marched on a main road in Islamabad, clashed briefly with police and demanded the release of all detainees.

There were no reports of violence at rallies elsewhere in the country, where hundreds of Islamic radicals also protested the crackdown on mosques and offices of outlawed groups in the aftermath of the July 7 suicide bombings in London.

Authorities say their aim is to purge the country of extremism.

Earlier, Hafiz Hussain Ahmad, a senior leader of the coalition, said the government had arrested a large number of innocent people to appease Western countries.

He said no terrorists were arrested in the raids on mosques and Islamic schools, or madrassas, and he demanded the release of all detainees.

On Thursday, Gen. Pervez Musharraf, the president, appealed to the nation in a televised address to "rise up and wage jihad against extremist elements," which he vowed to crush.

He also condemned those who carried out the London suicide attacks, which killed 56 people, including the four bombers.

A diplomatic official said Friday that Pakistani intelligence, acting on a tip from British authorities, has been looking for a man named Haroon Rashid Aswat, 31, who reportedly was in close contact with the alleged bombers.

The official, who spoke on condition of anonymity, said investigations were continuing and attempts to locate a record of Aswat's arrival in Pakistan were unsuccessful.

A diplomat in Islamabad, who also spoke on condition of anonymity, said Aswat was not in Pakistan.