“The man came and started shouting at us saying did we want our freedom or azadi, he seemed quite shaky,” said Reza, 25, a student at Jamia Millia Islamia University.

“He pulled out a gun and was pointing it at us. We had to come together and ask the man to lower his weapon after the police did nothing.”

The highly charged word "azadi" was previously associated with Kashmiri separatists, but has been used widely in the past more than a month of protests against the citizenship law.

The law makes it easier for persecuted religious minorities from three neighbouring countries to get Indian citizenship, but not if they are Muslim.

Critics say this forms part of Prime Minister Narendra Modi's master plan to remould India as a purely Hindu nation, marginalising its 200 million Muslims, something Modi denies.

Several thousand protesters descended on Jamia Millia Islamia University tonight to listen to speeches by civil society activists, claiming to have been re-energised by the shooting of the student.

“The government is trying to terrorise us and threaten us but if they bring weapons we won’t stop or step back. We are just going to get stronger, united together fighting for the right cause,” said Khan, 42.

Before Thursday's incident, the alleged gunman went live on Facebook as he walked around the protest area.

"On my last journey, take me draped in saffron and shout slogans of Hail Lord Ram," one post on his page read - a popular chant for Hindu nationalists.

Saffron is a colour associated with Hinduism - and with Modi's Hindu nationalist Bharatiya Janata Party - while Ram is an important deity.

"Shaheen Bagh, Game Over," read another, referring to massive protests against the citizenship law taken up by women and children in the Indian capital.

After the shooting several thousand people gathered at the site, an AFP reporter said.

Some pushed against barriers, and police responded with water cannon, media reports said.

BJP leader reportedly Manoj Tiwari linked the incident with alleged plans to assassinate Mr Modi.

"There were talks of shooting PM recently, now shooting has taken place," he told news agency ANI, adding: "The shooting incident proves that the people at the heart of the protest are violent in nature. They believe in bullets and bombs."