Indian police have arrested the student union president at a top university on sedition charges, following a protest over the hanging of a Kashmiri man.
Kanhaiya Kumar from Delhi's Jawaharlal Nehru University (JNU) was arrested following a rally against the 2013 hanging of Mohammed Afzal Guru at which anti-India slogans were allegedly used.
University teachers have criticised the arrest as "excessive police action".
Afzal Guru was convicted over a 2001 plot to attack India's parliament.
He had always denied plotting the attack, which was carried out by Kashmiri militants and left 14 dead.
Tuesday's protest against Afzal Guru's execution angered many of India's politicians.
Home Minister Rajnath Singh wrote on Twitter: "If anyone raises anti-India slogans and tries to raise questions on the nation's unity and integrity, they will not be spared."
Meanwhile, Education Minister Smriti Irani said: "The nation can never tolerate an insult to Mother India."
Police are searching for more students who attended Tuesday's protest.
Mr Kumar, who has been placed in police custody for three days, has reportedly denied the charges against him.
"I dissociate myself from the slogans which were shouted in the event. I have full faith in the Constitution of the country," he said, quoted by the Times of India.
The JNU Teachers Association has urged police to withdraw from campus and release Mr Kumar.
"We strongly believe that current excessive police action is totally uncalled for, and it has only aggravated situation." it said in a statement.
Correspondents say there has been a sharp rise in the number of sedition cases in recent years.
Last year, folk singer S Kovan was held on sedition charges after writing songs that criticised the local government for not banning alcohol sales.
And in 2014, the authorities in Uttar Pradesh brought sedition charges against a group of Kashmiri students, saying they had cheered the country's arch rival Pakistan in a cricket match. The charges were later dropped.