Former Chechen rebel Ramzan Kadyrov has been sworn in as president of Russia's troubled southern republic of Chechnya.
Mr Kadyrov became prime minister after his father was assassinated
Russia says he has restored stability and helped rebuild the capital, Grozny.
But human rights groups say he rules by fear, using a private militia to kidnap, torture and kill Chechens.
His inauguration marks the logical end of Moscow's policy of Chechenisation - handing over direct responsibility for running the region to ethnic Chechens.
'Hero of Russia'
Mr Kadyrov took the oath at his residence in Chechnya's second city, Gudermes.
Born in Tsentoroi, Chechnya in October 1976
At 16 he led a rebel group fighting Russian control of Chechnya but switched sides to back Moscow in the 90s
Appointed deputy Prime Minister after his father, ex-president Akhmad Kadyrov, was assassinated in 2004
Favours polygamy, and backs headscarves for women
At the Mrs World 2007 pageant, held in Chechnya, he proposed to "Mrs Kenya" Caroline Verkaik, apparently in jest
Russia's Itar-Tass news agency says he took the oath in the Russian language, keeping his hand on the Russian constitution, the Chechen constitution and the Koran.
The event crowns the remarkable transformation of a barely educated rebel fighter into a powerful regional figure and loyal servant of Moscow, the BBC's Russian affairs analyst Steven Eke says.
Mr Kadyrov was appointed prime minister of Chechnya after the assassination of his father, former pro-Moscow Chechen President Akhmad Kadyrov.
Ramzan Kadyrov quickly became the single most powerful individual in the republic, stamping his authority by using a feared private militia, known as the Kadyrovtsy.
He has received Russia's highest state honour - the Hero of Russia medal.
Russian and international human rights groups, as well as the Council of Europe, allege that the militia continues to commit serious crimes and human rights abuses - including extortion, kidnappings, torture and summary executions.
Both Mr Kadyrov and the Kremlin deny the allegations.
Moscow's policy of Chechenisation is not without risks, Steven Eke says.
Some Russians argue that, in setting Chechens against fellow Chechens, Moscow has gained short-term peace but opened the way to an eventual, inevitable civil war, in the long-term.
Others question Mr Kadyrov's loyalty to Russian President Vladimir Putin and Moscow - pointing to his dalliances with Sharia law, as well as his pledges to defend ethnic Chechens, who often experience racial discrimination, wherever they may be in other parts of Russia.