Kyrgyzstan opposition leader Kurmanbek Bakiev says he has been named acting president, a day after protests toppled the central Asian state's government.
Opposition leaders have pledged to restore order
Mr Bakiev, an economist, said he had been given the title in addition to that of acting prime minister.
A BBC correspondent in the capital, Bishkek, says calm has now returned after Thursday's scenes of violence.
Three people are reported to have been killed overnight, as looting swept the city and buildings were burnt down.
Opposition leaders have promised to prevent their victory disintegrating into chaos.
The opposition has now formed a so-called Council of People's Unity in an attempt to bring together various anti-government groups.
Confusion still surrounds the whereabouts of President Askar Akayev.
He is said to have fled the country with his family, with unconfirmed reports saying he is in neighbouring Kazakhstan.
Baktybek Abrissaev, Kyrgysztan's ambassador to the US, described the takeover as an illegal act.
Mr Akayev's administration was swept from power on Thursday, when thousands of anti-government demonstrators chanting "Down with the Akayev clans" gathered in Bishkek and stormed the presidential palace.
The huge protests were sparked by elections last month, which were widely seen as fraudulent.
But many other people joined in, motivated by anger about poverty, unemployment and official corruption, correspondents say.
The parliament, which was due to be replaced by the winners of the recent election, reconvened in emergency session late on Thursday to appoint a new leadership.
Kurmanbek Bakiev was named interim prime minister - and after a subsequent session on Friday, he said he had also been made acting president.
Another prominent opposition leader, Felix Kulov, who was released from jail by his supporters during the upheaval, was appointed head of the country's security ministries.
Ishenbai Kadyrbekov was elected as the group's new speaker, although the upper house of parliament had initially said he would be the new interim president.
There are fears of further instability in Kyrgyzstan, and foreign powers are watching the situation closely.
Anti-government protests had been gathering strength for weeks
US Secretary of State Condoleezza Rice said it was too soon to know where events in the country were leading.
"This is a process that's just beginning," she said, adding that the US would seek to "move this process of democracy forward".
Russia's reaction was more sceptical.
"I think that the so-called opposition... should have the brains to find enough strength to calm down and bring the situation to the plane of political dialogue and not a dialogue of screams, shattering windows, destroying buildings and freeing prisons of criminals," Defence Minister Sergei Ivanov said.
Kyrgyzstan is of strategic importance to Russia and the United States, both of which have military bases in the country.