ISLAMABAD -- Hundreds of radical Islamists who had rallied for four days in the heart of Pakistan's capital ended their demonstrations on Wednesday hours after the government threatened to use force to disperse them.

The Islamists were protesting last month's hanging of a policeman who had shot and killed a secular governor over his opposition to the country's strict blasphemy laws. They had demanded strict Shariah law and the hanging of a Christian woman the governor had defended against blasphemy allegations.

Awais Noorani, one of the protest leaders, called on the demonstrators to disperse, saying a deal was reached with the government.

Noorul Haq Qadri, who said he had helped negotiate the deal on behalf of the protesters, said the government had given assurances that there would be no attempt to amend the blasphemy laws and that it would release all detained protesters who were not wanted on other charges.

But Interior Minister Chaudhry Nisar Ali Khan said the government had not acceded to any of the protesters' demands. He said religious leaders had helped convince them to end their rallies.

Police have detained more than 1,000 protesters in the last four days, Khan said. He said those involved in violence would be prosecuted, while the rest would be freed after investigation.

The protests had paralyzed one of the busiest areas of Islamabad. Most of the businesses in the area and schools across the city remained closed.

More than 10,000 Islamists from Pakistan's Sunni Tehreek group descended on Islamabad on Sunday to denounce last month's hanging of officer Mumtaz Qadri for the 2011 murder of secular Gov. Salman Taseer.

Their rally turned violent and police fired tear gas on Sunday, but failed to disperse the protesters, who damaged bus stations, traffic lights and closed-circuit security cameras. The sit-in continued, but the number of protesters had dwindled to about 1,200.

Thousands of riot police and paramilitary troops had been deployed around the site, police official Nauman Alvi said. The government had warned that 7,000 security forces were ready to move in and disperse the demonstrators.

The protest comes against the backdrop of a massive suicide bombing by a breakaway Taliban faction that targeted Christians gathered for Eastern Sunday in a park in Lahore, killing 72 people, mostly Muslims.

Despite its hard-line views, the Sunni Tehreek group behind the protests in Islamabad does not carry out militant attacks.

Associated Press writer Munir Ahmed contributed to this report