Earlier in the week, women from the school raided a house they said was a brothel as part of a private anti-vice drive, abducting the woman who owned the house, two of her relatives and a baby.
Ghazi said the students had abducted the women after she refused to shut down her business.
Tension increased on Wednesday when security agencies arrested two female teachers from the school and two other followers in connection with the incident and imams from the mosque and their followers detained two policemen and seized two police vehicles in response.
Ghazi, who is said to have been involved in a bomb plot in 2004, said his religious students were still holding the three women they accused of prostitution, as well as the baby.
"We are asking the government to register a case against them for their release," Ghazi said, adding that the women would be set free if they repented and gave up prostitution.
Abdul Rashid Niazi, a senior police official, said the police were prepared to take "legal action" to have the women freed.
"We hope that they will release the women today, but if that does not happen we will take necessary legal action," he said.
The mosque's anti-vice drive comes as Pervez Musharraf, the Pakistani president, warned in a speech on Pakistan's national day of the spread of Islamist "extremism" in Pakistani society.
The authorities in Islamabad have for months also been at odds with religious leaders and their followers at the mosque, which is known locally for its anti-government and anti-US stand, over government attempts to demolish mosques illegally built on public land.
Women from the religious school occupied a library next to their mosque in January to protest against efforts by the city authorities to demolish illegally built mosques.
City authorities had offered alternative sites for mosques earmarked for demolition, though they later abandoned the campaign.
But students are still occupying the library, demanding several demolished mosques be rebuilt.
Many Pakistanis have been dismayed by the behaviour of the mosque's students and religious leaders and are concerned by what they see as the government's failure to act against the first Taliban-style action seen in Islamabad, Pakistan's capital.