Tens of thousands of people protested across Pakistan on Friday against the siege and storming operation ordered by President Pervez Musharraf at Islamabad's radical Lal Masjid that resulted in at least 108 deaths.
Meanwhile, amid fears of major retaliatory attacks by militants, police in the northwestern city of Dera Ismail Khan arrested three men with seven explosive vests for suicide attacks and car packed with more explosives.
As well as demonstrations in the capital and other major cities such as Karachi, Lahore, Quetta and Peshawar, some 5,000 people, including many students from Islamic seminaries, took to the streets in Dera Ghazi Khan in the central Punjab province.
Crowds condemned the action at the Red Mosque and the adjoining madrassa, and waved placards bearing such slogans as "Musharraf is America's pet."
"Musharraf has shed the blood of hundreds of innocents only to please his Western masters," local cleric Maulana Rehmatullah told the protesters.
The battle that erupted on Tuesday ended a long confrontation with radical clerics whose students resorted to kidnapping citizens and police officers in their quest for enforcement of strict Islamic law in Pakistan. Foreign fighters with stockpiles of heavy weaponry were also present in the complex, officials said.
The call for countrywide protests came from Wafaq-ul-Madaris, a powerful body of religious scholars that represents more than 10,000 madrassas, and the Muttahida Majlis-e-Amal (MMA) alliance of religious political parties.
Hundreds more protesters blocked a central avenue in Islamabad about two kilometres from the devastated mosque complex amid loud displays of mourning for students who died.
"The issue could have been resolved through dialogue but the government deliberately caused the failure of last-minute efforts toward a negotiated solution," MMA parliamentarian Maulana Abdul Ghafoor Haidry told the gathering.
Hundreds of people also offered prayers at the grave of Abdul Rashid Ghazi, the deputy chief cleric of the complex who died in the fighting and was buried in his home village in southern Punjab on Thursday.
Meanwhile, authorities boosted security in anticipation of disturbances and attacks by Red Mosque sympathizers.
Some 10,000 paramilitary troops were deployed in Karachi around the southern port city's official buildings and 12 of largest madrassas.
More troops were also deployed in several districts of the restive North-West Frontier Province (NWFP), where more than two dozen people have died in revenge bombings since the mosque siege began on July 3.
Army units sealed off approaches to the NWFP town of Hangu where several members of the security forces were killed and injured in suicide bombings Thursday, the Dawn news channel reported.
In the town of Dera Ismail Khan, police sources said two of three suspected suicide bombers who were detained, came from the restive tribal region of North Waziristan, a known hotbed of militant organizers of attacks on other cities.
Police also recovered 100 rockets, mortar shells and anti-tank mines at a house used by the men.