He wrote on Twitter that he was then contacted by the country's Central Bureau of Investigation (CBI) and told he was prevented from leaving "because of the case Modi govt has filed against Amnesty International India."

Amnesty has been a vocal critic of the Modi government's treatment of minorities and alleged abuses by Indian security forces in the disputed territory of Kashmir.

It halted its India operations in 2020 after the government froze its bank accounts in what the group said was part of an official "witch hunt".

Amnesty's Bangalore offices had been raided two years earlier by the Enforcement Directorate, which investigates financial crimes in India.

The group had also faced sedition charges, later dropped, over a 2016 event to discuss human rights violations in Kashmir.

Last week, prominent Indian activist and writer Rana Ayyub was prevented from flying to London to speak about the intimidation of journalists in India.

Ayyub, a fierce government critic, tweeted that she was stopped at the Mumbai airport because of a probe into an alleged money laundering case against her.

Delhi's high court gave the 37-year-old permission to fly on Monday.