Human rights groups say they are appalled at the appointment of Ramzan Kadyrov as Chechnya's new president.
Mr Kadyrov is a former rebel fighter who switched sides to Moscow.
He is accused of widespread human rights abuses, including kidnap and murder, from his time as prime minister.
His appointment was endorsed by the Chechen parliament after being nominated by the Russian President, Vladimir Putin, on Thursday.
Separately, the Council of Europe's human rights chief, Thomas Hammarberg, said he had found evidence of widespread human rights abuses during a visit to the area this past week.
Mr Hammarberg called for a commission to be set up to discover the fate of the estimated 2,600 people who disappeared in Chechnya without trace during two wars since 1994.
