Vladimir Putin is sworn in as the new Russian president during a ceremony at the Kremlin in Moscow, May 7, 2012. (Image: Reuters)
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 outgoing president Dmitry Medvedev.
The ceremony took place in the Hall of the Order of St. Andrew in the Grand Kremlin Palace in front of a specially invited audience of the Russian elite including his rarely-seen wife Lyudmila.
Putin already served as president for two terms between 2000 and 2008 but ceded the Kremlin to Medvedev four years ago after serving the maximum two mandates allowed.
Medvedev, widely mocked as a seat-warmer for the real Russian number one who failed to implement real change, is expected later in the week to take on Putin's last job as prime minister.
Despite winning March 4 presidential elections with 63.6% of the vote, analysts say Putin now faces unprecedented challenges in his third Kremlin term after mass opposition protests and an explosion in Internet use.
Under Medvedev's presidency, the presidential mandate was extended to six years from four. If Putin stays in power the full term to 2018, he will equal Soviet leader Leonid Brezhenv as the longest serving Moscow leader since Stalin.