Vladimir Putin was sworn-in as Russia's president for a fourth term, extending his almost two-decade rule by another six years at a time of high tension with his Western rivals.
The 65-year-old, in power since 1999, is on course to become the longest-serving Russian leader since Joseph Stalin after his victory in March's elections.
Putin won nearly 77 percent of the vote in polls which his most vocal opponent was banned from running in.
He has promised to use his fourth term to revitalise the country's economy. But he also faces a host of delicate international disputes.
"I consider it my duty and my life's aim to do everything possible for Russia, for its present and for its future," Putin said at swearing-in ceremony, with his hand on the Russian constitution.
"I feel strongly conscious of my colossal responsibility," he said, thanking Russians for their "sincere support" and "cohesiveness." "We have revived pride in our fatherland," Putin said.
"As head of state I will do all I can to multiply the strength, prosperity and fame of Russia."