Kurmanbek Bakiev has been officially inaugurated as president of Kyrgyzstan, a month after winning the Central Asian state's elections.
Kurmanbek Bakiev won a landslide victory in elections in July
Mr Bakiev scored a landslide victory in the poll, winning 89% of the votes.
He had been appointed acting president in March, following the downfall of long-serving former leader Askar Akayev, who fled into exile.
Mr Bakiev, 55, who praised the conduct of the July elections, has said his main goal is to eradicate corruption.
He took the oath of office on the country's constitution in front of dignitaries in Bishkek's central square, following a military parade.
Mr Bakiev has said he will expect professionalism from members of his government, who he says will serve on the basis of merit rather than connections.
The president must also seek to improve the economy of a country in which 40% of people live below the poverty line.
Analysts say Kyrgyzstan will have to develop industries such as tourism, hydro-electric power and mining if it is to create new jobs for its 5m citizens.
In his first post-election comments, Mr Bakiev questioned the need for the US to continue to have an airbase in Kyrgyzstan.
The Pentagon has since been told it can keep its base in Kyrgyzstan - but only for as long as it is needed for operations in Afghanistan. US-led forces have been stationed at the site near the capital, Bishkek, since 2001.
Ahead of the elections, Mr Bakiev's only significant political rival was thought to be Felix Kulov.
The two men agreed to a power-sharing pact, by which Mr Kulov would serve as prime minister if Mr Bakiev became president.