Vladimir Putin was sworn in as Russia's president for a historic fourth term at a ceremony in the Kremlin on Monday, extending his almost two-decade rule by another six years. 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. Mr Putin was re-elected with more than 76 percent of the vote, his best ever election performance. He has promised to use his fourth term to revitalise the country's economy, but he also faces a host of delicate international disputes.