Billionaire financier George Soros is to donate $100 million (€78m) to Human Rights Watch over the next 10 years.
The grant from the Open Society Foundations is the largest Mr Soros has ever made to a non-governmental organisation.
The gift is the first in a series of large donations he intends to make, Mr Soros (80) said in an interview published in the New York Times today.
"This is partly due to age," he said.
The terms of the grant challenge New York-based Human Rights Watch to raise another $100 million in private contributions on its own, a goal it expects to meet, the organisation said.
"Human Rights Watch is one of the most effective organisations I support," Mr Soros said in a statement. "Human Rights Watch can have even greater impact by being genuinely international in scope."
The grant is intended to help the watchdog group expand internationally to staff offices in key world capitals and enhance research into "countries of concern," it said.
The Times said Mr Soros has given about $700 million to various causes this year, including the Human Rights Watch donation. Forbes magazine estimated Mr Soros' fortune at $14 billion this year.
Reuters