It was my first visit to Jawaharlal Nehru University, one of India’s most prestigious academic institutions, but it felt like I was entering a war zone.

On Sunday, just after sunset, a masked mob armed with sticks and stones had attacked students and teachers on the campus of JNU, in the heart of the Indian capital.

More than 20 people were injured in the violence, which students say was carried out by the ABVP, a student organisation with deep ties to the ideological wing of the ruling Hindu nationalist Bharatiya Janata party. Videos circulating on social media appear to show the Delhi police, who report to home minister Amit Shah, escorting the mob off campus, raising questions over their impartiality.

Hours after the attack, all roads leading to the main gate of the leafy university site were closed and barricaded. Hundreds of police wearing riot gear and armed with lathis (long sticks) patrolled the area. Terrified students lugging their bags away were fleeing the campus to stay with friends.

A crowd of students, faculty and reporters milled around the Sabarmati accommodation block where the mob had rampaged the night before. The windows of the front doors had been smashed and, as I walked through the entrance, broken glass crunched under my feet.

The scene was the result of an ideological war that is being waged on campus, a microcosm of the continuing fight over the wider direction of India, the world’s largest democracy, as it lurches away from its secular foundations.

The face of BR Ambedkar, the father of the Indian constitution who advocated secularism and rejected the idea of Hindu rule, was spray-painted on one door. On others were the saffron-coloured ABVP posters warning against “red terror”. Students and professors say it was the ABVP who instigated the violence. They ran through the halls shouting the battle cry of the Hindu right — “Jai Shri Ram” — and targeting the rooms of leftist activists and Muslims.

“It’s horrible, I can’t sleep, I think maybe I’ll be lynched because I’m a Muslim,” one PhD student told me. “I used to think JNU was the safest place in India, I can’t say that any more.”

Outside the hostel, JNU faculty had gathered to protest against what they say is part of an ongoing crackdown by the BJP against liberalism in India.

“For these populist administrations all around the world, higher education is the first thing that comes under attack,” said Madhu Sahni, a professor of German who has been at the university for more than 30 years.

In response, BJP officials have gone on the offensive, claiming the violence was initiated by “leftist hoodlums” and deploying its vast cyber army to smear anyone with an opposing viewpoint as an “anti-national”.

The campus siege has once again put the spotlight on India’s handling of dissent in the wake of its heavy-handed response to protests against a contentious citizenship bill. The events at JNU show prime minister Narendra Modi is “licensing the militarisation of domestic politics”, warns academic Pratap Bhanu Mehta.

Last year saw the Modi government, now in its second term, flex its power to reshape India as a Hindu homeland. It passed a bill to criminalise Islamic instant divorce and ended the special status of Jammu and Kashmir, flooding India’s only Muslim-majority region with troops and putting it on digital lockdown.

The backlash to the citizenship law was a watershed for Indian politics, marking the first serious revolt to Mr Modi’s Hindu-first agenda. Still, the government, which was voted in with a crushing majority in May, is unmoved. At a rally this month in the city of Jodhpur, Mr Shah said “we won’t backtrack even an inch”.

The protests, which are becoming more organised each day, show that Indians are willing to fight for a secular country — or at least for the ideal of one. The combination of a rigid ruling party with an emboldened opposition sets the stage for more turmoil this year against a backdrop of a prolonged economic slowdown.

As I talked to the students, it became clear that the violence had only added impetus to the anti-government movement. “This is the unfolding of the dream that we didn’t want,” said student Geeta Thatra. “This is an India we reject”.