Authorities in Pakistan's eastern Punjab province shut all schools and universities for two days on Friday in an attempt to contain the spread of protests by students over an alleged on-campus rape.

The closures in Pakistan's most populous province affect an estimated 18 million students.

Tensions have been high on college campuses since reports of the alleged rape in the eastern city of Lahore spread on social media, and protests have broken out in four cities. In Gujrat in Punjab province, a security guard died in clashes between student protesters and police on Wednesday.

Police arrested a person in connection with the death.

The government and police have denied that any rape occurred on a campus of the private Punjab Group of Colleges in Lahore, the capital of Punjab. They are seeking the arrest of nearly three dozen people, including several journalists, saying they spread misinformation on social media that led to the protests.

Students, however, announced they would hold a rally later Friday to demand justice for the alleged victim in the northwestern Khyber Pakhtunkhwa province bordering Afghanistan.

The decision to shut all schools in Punjab came a day after hundreds of students ransacked a college building in the garrison city of Rawalpindi. Police fired tear gas and charged at the students, arresting more than 250 people.

The protests appear to have begun spontaneously, as student unions have been banned in Pakistan since 1984. There are no organisations representing students, although political parties' youth wings exist.

Separately, the political party of imprisoned former Prime Minister Imran Khan announced it will hold protests across the country on Friday to oppose any amendments to the country's Constitution.

Khan's supporters say Prime Minister Shehbaz Sharif, who replaced Khan after his ouster in 2022 in a no-confidence vote in parliament, wants to appoint judges of his own choosing and set up a new constitutional court in parallel with the Supreme Court. The government denies the allegations.

Sexual violence against women is common in Pakistan but is underreported because of stigma in the conservative country. Protests about the issue have been rare.