Islamabad police on Saturday registered eight cases related to the alleged kidnapping and torture of four police officers by members of religious groups led by the Tehreek-e-Labaik Yah Rasool Allah Pakistan (TLY) and Sunni Tehreek Pakistan (ST) whose protests have disrupted life in the twin cities for three days running.

The policemen, who were abducted by protesters on Friday night, were released early morning on Saturday.

Religious parties have been protesting a lack of punishment for those involved in making changes to the Khatm-i-Nabuwat declaration for electoral candidates, which the government insists was a result of a clerical error and has since then been reversed.

Former NA-120 candidate Azhar Hussain and Pir Aijaz Afzal are among those participating in the protests demanding the removal of Law Minister Zahid Hamid over the controversy.

The protesters, led by TLY leader Khadim Hussain Rizvi, have already been booked in three cases earlier for the death of a child, violence against the crew of a TV channel and violation of Section 144.

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Today's FIRs were registered under Section 7 of the the Anti-Terrorism Act (ATA) and multiple sections of the Pakistan Penal Code (PPC) which relate to serious offences, including kidnapping, rioting and assault of a public servant.

Of the eight registered cases, four were registered at the I-9 police station, three at the Khanna police station and one at the Aabpara police station, and TLY's Khadim Hussain Rizvi and others have been named as suspects in the FIRs.

The FIRs, registered by police officers as complainants, claimed that a wireless set and a camera were snatched and police officials were kidnapped by the protesters. The complainants also alleged the protesters had opened fire on them but they escaped unhurt.

The protests, which began with a few hundred members of the TLY who had gathered earlier this week at the main Faizabad crossing outside Islamabad, grew to over 3,000 by Friday afternoon, disrupting public life and prompting police to set up shipping containers to prevent the protesters from entering the city.

The leaders of the religious parties staging the sit-in also threatened to attack the families of federal ministers if their demands were not met.