Residents of the eastern Uzbek city of Andijan say they fear hundreds of people may have been killed during the suppression of mass protests there.
Thousands tried to flee the city centre as Uzbek troops moved in
Witnesses said they saw troops loading dozens of bodies onto trucks.
Government forces appear to have regained control of the city after Friday's demonstrations, but the situation is still said to be tense.
There are rebel gunmen based in the city's administrative headquarters, according to some reports.
No security forces are immediately visible around the city centre.
Sporadic shooting is continuing, and the BBC's Monica Whitlock says hundreds of people are now walking back towards the centre of town.
Angry residents denounced the authorities.
"Down with [President Islam] Karimov who fires on his own people," a group of people shouted near the government building, quoted by AFP news agency.
Friday saw troops open fire on huge crowds and exchange fire with armed protesters.
Hospital officials told the BBC that at least 50 had died and many more were wounded throughout the day.
Tensions flared in Andijan on Thursday night when thousands of prisoners were freed from a city jail by a crowd angry at the imprisonment of 23 local men on charges of Islamic extremism.
Uzbek officials refused to negotiate with the protesters, who they branded as "rebels".
Chaos and violence
The violence prompted international concern. In the US, White House spokesman Scott McClellan called for both sides to show restraint.
The EU criticised Uzbek leaders for not paying enough attention to human rights, the rule of law and relieving poverty.
Violence broke out after thousands gathered in Andijan's main square on Friday calling for "justice" and "freedom".
President Karimov was said to have taken personal control of the operation to crush the protests. Unconfirmed reports later said he had returned to the capital, Tashkent.
Armoured vehicles carrying Uzbek troops arrived in the square, where protesters had seized the mayor's office, and opened fire.
Men, women and children fled the square in panic as protesters occupying the mayor's office reportedly returned fire.
Eyewitnesses in the square told how protesters lay flat on the ground as troops fired into the crowds. One spoke of "indiscriminate firing", and said she saw "bloody corpses" lying in a ditch.
Doctors from neighbouring towns and cities were ordered into Andijan or placed on standby on Friday night, the Associated Press news agency reports.
Mr Karimov has taken a tough line on security since a spate of suicide bombings last year, blamed on Islamic extremists.
But critics of Mr Karimov say his policies have heightened tensions among many poor Uzbeks.
Andijan is the barometer of feeling for a long, densely-populated valley called Ferghana with a long tradition of independent thought, and the authoritarian government in Tashkent has always eyed the valley with suspicion, says the BBC's Monica Whitlock, in Uzbekistan.
The government has locked up probably thousands of local young men, many of them prominent members of the community, accusing them of Islamic extremism.
The violence prompted neighbouring Tajikistan and Kyrgyzstan to shut their borders with Uzbekistan. Protests in Kyrgyzstan in March resulted in the overthrow of its then President, Askar Akayev.