"They were shouting: 'We will not allow any un-Islamic practice'," recalled one of the students, who was reluctant to give his name.
"Girls hid behind cement pillars in terror as they fled chanting 'Revolution, revolution, Islamic revolution'," he said of the event that took place last week.
Pakistani liberals say the rampage was symptomatic of rising religious intolerance in the 56-year-old Islamic republic.
"This ... showed extremism is gaining ground," said Tausif Ahmad, a professor of mass media and communications at Karachi's Federal Urdu College.
Hardline Islamist parties aligned under the Muttahida Majlis-e-Amal (MMA) coalition surged to power in two provinces in national elections last year and won spectacular gains in the federal parliament, where they now lead a combined opposition and effectively hold the balance of power.
The Islamist parties have pledged to enforce already existing Islamic sharia law, and are encouraging interest-free banking and segregated education.
"On their orders, drama, theater and musical events are forbidden, as is any other activity that brings male and female
At the same time President Pervez Musharraf has been waging a high-profile campaign for "moderate" Islam, both at home and on the world stage.
Pervez Hoodbhoy, a columnist and professor of physics at
Islamabad's Qaid-e-Azam university, believes religious vigilantes are suppressing any flourishing of intellectualism and arts.
"On their orders, drama, theatre and musical events are
forbidden, as is any other activity that brings male and female
students together," he said.
One of the capital's few cinemas was torched to the ground by fanatical religious students rampaging after funeral prayers for slain hardline Sunni Muslim leader and MP, Azam Tariq, on 7 October. A worker inside the cinema died in the flames.
Senior psychiatrist Harun Ahmad said many of Pakistan's 10,000 religious schools, known as madrassas, are brainwashing the children of poverty-stricken families, who cannot afford any other form of education.
Plans to reform religious schools
have been rejected by leaders
"Faith does not call for logic and thousands of young minds have been brainwashed by madrassas, which need to be reformed," said Ahmad.
Government plans to regulate the madrassas, and enforce
syllabuses broader than rote Quranic learning, have been rejected by madrassa leaders.
"There is no fault in our system. We only tried to produce the
best Muslims who can also compete with the computer generation," said Federation of Madrassas spokesman Mufti Muhammad Jamil. "Madrassas don't teach killings, even of infidels."