Bangladesh deployed a paramilitary force on Tuesday after at least five people were killed during violent demonstrations by thousands of university students, raising the specter of instability in a country familiar with protests.

For weeks, students across Bangladesh have been protesting quotas for government jobs that were recently reinstated after being abolished in 2018 following another countrywide student protest.

Demonstrations intensified in recent days, with parts of the capital, Dhaka, blockaded and students refusing to attend classes. Even female students — who are not allowed out of their dorms after 9 p.m. — broke the rules to join the protests, a measure of the gravity of the situation.

The protests were first started by students of the University of Dhaka, the nation’s pre-eminent institution, and have spread to other universities and cities and turned increasingly political, pitting the ruling party against the opposition.

Since the protests began roughly two weeks ago, hundreds of demonstrators have been injured in clashes with the police and with counter protesters. Citing the safety of students, government officials announced late on Tuesday that they would shut down most schools and colleges indefinitely. Facebook, the main social media platform that protesters used to organize and share news, was partially unavailable as of Tuesday night.

The demonstrations started in early July after a Dhaka court overturned a 2018 decision by the government of Prime Minister Sheikh Hasina to abolish the country’s job quota system, which had existed for decades.

The system reserved more than 50 percent of lucrative government jobs for quota holders, including women and those with disabilities. They were initially devised as a way to reward those who fought for the country’s freedom from Pakistan in 1971, ensuring that their descendants would always be provided for. The latest ruling reinstated a 30 percent quota for those descendants.

Student activists have argued that most of the government jobs should be given on merit.

“Students will not leave the streets until this demand is met,” Nahid Islam, a coordinator of the protests, said at a gathering in Dhaka on Tuesday.

Sheikh Mujibur Rahman, the founding leader of Bangladesh, created the quota system in 1972, only for his daughter Ms. Hasina to abolish it in October 2018 after students protested the dismissal of a writ appeal some of their peers had made earlier that year to change the system. Families of freedom fighters then protested, and the court sided with them last month.

In explaining the rationale for her 2018 decision, Ms. Hasina said at a news conference on July 14 that she had become “very annoyed” by the incidents the students were causing, including attacking the office of her political party, The Awami League. Referring to them as “some so-called intellectuals sitting in their house and recording false propaganda to spread,” Ms. Hasina added: “At one point, I said, let’s just abolish the quota system. The purpose of this was to see what would happen if the quota system was abolished.”

Graphic images and videos circulating on social media show men beating female students, while others contain images of wounded students lying on the floor of Dhaka Medical College Hospital.

Earlier this week, members of the student wing of the Awami League began attacking student protesters, even as police officers fanned out across Dhaka and other cities to curb the violence.

Obaidul Quader, an influential leader of the ruling party, said their student wing would “respond to those displaying arrogant behavior,” referring to the protesters.

On Tuesday, the quota fight became overtly political when Asaduzzaman Khan, the home minister of Bangladesh, pointed his fingers at the Bangladesh Nationalist Party, the main opposition party, saying their members may be involved in the violence.

In turn, the B.N.P. leader, Mirza Fakhrul Islam Alamgir, urged everyone to join the protests.