The Vice President of Russia's main business lobby group, Igor Yurgens, resigned from Russia's Presidential Human Rights Council on Monday night, the latest in a string of activists to quit the group.
Yurgens, who is also chairman of the Institute for Contemporary Development think-tank, announced his decision on the Institute's website.
"I inform you that I have taken a decision to leave the council," he said.
Yurgens is the third member of the council to have left this week.
Valentin Gefter and Soviet-era dissident and activist Boris Pustyntsev also gave notice on Monday.
Thirteen other members of the council, including Moscow Helsinki Group head Lyudmila Alexeyeva and Transparency International Russian director Elena Panfilova, have tendered their resignations since December's disputed parliamentary elections.
Council head Mikhail Fedotov has said he would also resign if more than a half of the body's members leave.
The council, which has fluctuated in size over the years, has had as many as 40 members.
