Vladimir Putin today began a historic third term as Russian president in a glittering Kremlin ceremony overshadowed by the arrests of hundreds in protests against his 12-year domination of Russia.
Putin, head of state from 2000-2008, took over from outgoing president Dmitry Medvedev swearing to protect the rights of Russian citizens and also pledging a "new stage" in Russia's development.
The Kremlin bells echoed across Moscow and the presidential guard donned Tsarist-era uniforms for the brief but spectacular inauguration whose guests included old friends of Putin including Italian ex-premier Silvio Berlusconi.
Placing his hand on a copy of the constitution, Putin swore to "respect and protect the rights and freedoms of the people" and defend Russia's security as he officially took over from Medvedev.
Yet activists accuse Putin of systematically sacrificing rights in the pursuit of stability and lacking legitimacy after his knockout March 4 election victory with 63.6 percent of the vote, which was marred by claims of fraud.
The eve of the ceremony saw the worst clashes yet between police and anti-Putin protestors when a mass opposition demonstration descended into chaos and security forces wielded their batons to arrest hundreds of people.
Police said that 436 people were detained at Sunday's protest, including the anti-Putin leaders Alexei Navalny and Sergei Udaltsov who now face the prospect of spending at least the next two weeks in jail.
On Monday, Moscow police had arrested another 120 people, including liberal opposition leader Boris Nemtsov, during an unsanctioned rally against the inauguration close to the Kremlin walls. Police said they would all be released after a warning.
The mass arrests were in stark contrast to peaceful mass anti-Putin protests last winter which smashed the taboo against big opposition rallies. For the first time, both police and opposition said dozens in their ranks had been injured.
But Putin said in a brief speech after his swearing-in that Russia was now "reborn" and vowed to take it to a "new stage" of development during his six-year Kremlin mandate.
"We will have to decide tasks of a new level, a new quality and scale. The coming years will be decisive for Russia's fate for decades to come," he said.
Committing to project a strong Russia in foreign policy, Putin said Moscow would be a "reliable, open, honest and predictable partner" but also "the centre of gravity for the entire Eurasia."
The inauguration was marked by needle-sharp choreography, with Putin driven from the government headquarters through eerily deserted Moscow streets blocked off by police and then into the Kremlin itself.
As well as Berlusconi, other notable guests included Putin's wife Lyudmila, who has been rarely seen in public in recent years, and the last Soviet leader Mikhail Gorbachev.
Minutes after the Kremlin ceremony, Medvedev passed Putin the black "nuclear suitcase" with the codes that control the country's vast nuclear arsenal, official images showed.
Guests at a lavish reception later would be served finest Russian dishes including sturgeon steak and smoked cod washed down by Kremlin vodka and an astonishing 5,000 bottles of 2008 Abrau Durso "shampanskoye" -- Russian sparkling wine, RIA Novosti reported.
Medvedev has served as president since 2008 as Putin was constitutionally barred from serving more than two consecutive terms, having become head of state in 2000 following the resignation of Boris Yeltsin.
Putin remained in full charge as he instead took the job of prime minister. Yet analysts say he now faces the unprecedented challenge of a six-year term at a time when society is rapidly changing due largely to exploding Internet use.
Medvedev is expected to take on Putin's old job as prime minister but remain largely in the shadows, after his presidency failed to deliver initial promises of political and economic modernisation.