Medvedev became Russia's third president during the swearing-in ceremony in front of 2,500 guests at the Grand Kremlin Palace in Moscow, succeeding Vladimir Putin, reported Novosti, the Russian news agency.

After being sworn in on a copy of the Russian constitution, Medvedev spoke to the audience, pledging to "respect and protect human and civil rights," as well as defend Russia, the report said.

The most critical task, Medvedev said, "is to further develop civil and economic freedoms and crease new civil opportunities."

In his final speech as president, Putin wished his protege luck and success in the post. Putin will become Russia's prime minister and will head the ruling United Russia party.