Vladimir Putin has been sworn in as Russia's president at a glittering ceremony, hours after clashes between police and protesters laid bare the deep divisions over his return to the Kremlin for six more years.
The former KGB spy took his oath on Monday before nearly 2,000 guests in the Kremlin's St Andrew Hall, the former throne room with sparkling chandeliers, gilded pillars and high Gothic vaults.
Placing his hand on a copy of the constitution, he swore to "respect and protect the rights and freedoms of the people" and defend Russia's security as he officially took over from outgoing President Dmitry Medvedev.
Putin was blessed by Orthodox Church Patriarch Kirill before he delivered a brief speech at the inaugural hall.
"I will do all I can to justify the faith of millions of our citizens. I consider it to be the meaning of my whole life and
my obligation to serve my fatherland and our people," he said.
Putin will go on to inspect the Kremlin presidential guard and host a lavish reception featuring only Russian food and drink.
Although he has remained Russia's de facto leader for the past four years as prime minister, Putin takes back the formal reins of power he ceded to his ally Medvedev in 2008, after eight years as president.
Putin is returning with his authority weakened by months of protests that have polarised Russia and left him facing a battle to re-assert himself or risk being sidelined by the powerful business and political elites whose backing is vital.
Some opposition activists staged a small anti-Putin demonstration in the capital during the inauguration ceremony, Al Jazeera's Sue Turton reported.
"Over 100 people were arrested after chanting some anti-Putin slogans. The demonstrators were chanting against pro-Putin supporters, who were also arrested," she said, adding that there was no real disturbance caused.
"What is important is there is still a constituency, and the most modernised constituency in Russia, that does not see Putin as a desired president"
- Maria Lipman, political analyst
There were mass protests on Sunday, after which police detained more than 400 people, including three opposition leaders.
Tensions had increased at the rally attended by about 20,000 anti-Putin demonstrators near the Kremlin.
Police hit protesters with batons as they tried to stop demonstrators advancing towards them, carrying metal crowd barriers and throwing objects. The crowd fought back with flagpoles before the police eventually restored order.
Those arrested on Sunday included Alexei Navalny, the anti-corruption activist, liberal leader Boris Nemtsov and ultra-left wing leader Sergei Udaltsov.
The protesters marched shouting "enough lies" while helmeted police, using batons, beat back dozens of mostly young protesters at the event across the river from the Kremlin.
The turnout appeared smaller than most of the winter's unprecedented wave of protests, some of which attracted crowds estimated at 100,000 or more.
"The mass protests are maybe losing momentum and may be on decline, however what is important is there is still a constituency, and the most modernised constituency in Russia, that does not see Putin as a desired president," Maria Lipman, a political analyst from the Carnegie Endowment for International Peace, told Al Jazeera from Moscow on Sunday.
"I think that part of society will not reconcile to the fact that Putin holds power for the next six years, and we may see more eruptions of discontent in the following years over various kinds of developments."
National parliamentary elections were marred by fraud, but Putin won the vote easily and another round in March, returning to the Kremlin seat he held from 2000 to 2008.
Some of the demonstrators acknowledged that Putin's election win and his inauguration had been a blow to morale.
"It's true that some have been disappointed," said Yuri Baranov, a 46-year-old information technology specialist. But "the most important thing is that people have awakened".
A few kilometres across Moscow, several thousand people staged a rally supporting Putin, seen by his backers as
the only leader capable of defending Russia's interests on the world stage and the guardian of the economy at home.
While Putin's critics are tired of a political system that concentrates power in one man, many of his supporters welcome his domination of the country of more than 140 million.