They torched police cars on Saturday and attacked border guards in a second day of violence after bloodshed that witnesses said left hundreds dead.
Uzbek President Islam Karimov blamed "Islamic extremists" for the uprising in Andijan, the ex-Soviet republic's fourth-largest city.
But relatives of the dead angrily denounced authorities as they collected bodies and washed blood from the streets of Andijan, a day after troops fired into a crowd there that included women and children.
Kyrgyz border guards turned back about 6000 Uzbeks who were trying to flee Uzbekistan.
Some of those rushing to the border assaulted authorities and took control of government buildings in the village of Korasuv, 50km east of Andijan.
Russian President Vladimir Putin phoned Karimov to express concerns that Central Asia could be destabilised by fighting that broke out on Friday after protesters stormed a prison and occupied the local government offices before government forces put down the uprising.
The protesters' goal appeared to be releasing 23 men who were on trial for alleged Islamic extremism. Their supporters say they are victims of religious repression.
Karimov's hardline secular government long has cracked down on Muslims who worship outside state-approved mosques, and observers have warned of a possible Islamist uprising after the authoritarian leader in neighbouring Kyrgyzstan was ousted in March.
However, none of the protesters mentioned political or religious demands at Friday's protest - their complaints focused on the poor economic situation in Uzbekistan.
"To accept their [the protesters'] terms would mean that we are setting a precedent that no other country in the world would accept"
The Uzbek leader said 10 government soldiers and many more protesters died in Friday's fighting.
Witnesses said 200 to 300 people were shot dead, and an AP reporter saw at least 30 bodies in Andijan. Karimov said at least 100 people were wounded, although he did not say who fired first.
He said negotiations with the protesters collapsed after they demanded all their followers be released from jails across the Fergana Valley, Central Asia's conservative heartland.
"To accept their terms would mean that we are setting a precedent that no other country in the world would accept," Karimov told a news conference in the capital, Tashkent.
Outlawed Islamic party
Karimov claimed the uprising was orchestrated by a faction of Hizb-ut-Tahrir, a banned movement seeking to create an Islamic state in Central Asia.
Hizb-ut-Tahrir has long been targeted by the Uzbek government in a campaign that has been one of human rights activists' top grievances against the authoritarian government.
On Saturday in Korasuv, protesters set police offices on fire and vandalised their vehicles, a Kyrgyz official said. Uzbek helicopters were seen circling overhead.
Islam Karimov has been accused
of widespread abuses
In Andijan, about 1000 protesters marched in the streets.
Hundreds gathered at the site of the earlier violence, placing six bodies on display from the scores witnesses said were killed in fighting. Clusters of bystanders watched as men covered other bloodied bodies with white shrouds.
Demonstrators, some with tears in their eyes, condemned the government for firing on women and children.
Residents said a group of hundreds later went to a local police station to confront the heavily armed authorities, who sent a helicopter buzzing low over the crowd to scare them away.
Karimov said the activists were trying to follow the pattern set earlier this year where demonstrations brought down the government in neighbouring Kyrgyzstan.
He said he ordered authorities not to take any physical action against the demonstrators on Saturday. "In Uzbekistan, nobody fights against women, children or the elderly," he said.
By evening, only about 200 protesters remained in the centre of Andijan, residents said.
"Our women and children are dying"
In Friday's stand-off, Karimov said the government had offered the demonstrators free passage out of the city in buses with their weapons, seized in attacks on a police station and military outpost.
But a protest leader, Kabuljon Parpiyev, said Interior Minister Zakir Almatov did not sound willing to negotiate when they spoke by phone on Friday.
"'We don't care if 200, 300 or 400 people die. We have force and we will chuck you out of there anyway,'" Parpiyev quoted Almatov as saying.
Earlier on Saturday, soldiers loaded scores of bodies onto four trucks and a bus after blocking friends and relatives from collecting them, witnesses said.
Lutfulo Shamsutdinov, head of the Independent Human Rights Organisation of Uzbekistan, said he saw bodies of about 200 victims being loaded onto trucks near the square.
A witness in central Andijan told The Associated Press that "many, many dead bodies are stacked up by a school near the square".
Daniyar Akbarov, 24, joined the protests on Saturday after being freed from the prison during the earlier clashes.
Scores have been killed in the
"Our women and children are dying," he said, tearfully beating his chest with his fists. Akbarov said he saw at least 300 people killed.
The focus of the jailbreak was 23 men charged with membership in a group allegedly allied with Hizb-ut-Tahrir, which seeks to create a worldwide Islamic state and has been forced underground throughout most of Central Asia and Russia.
The men are alleged members of Akramia - a group named for their founder, Akram Yuldashev, an Islamic dissident sentenced in 1999 to 17 years in prison for allegedly urging Karimov's ouster. He has proclaimed his innocence.
The group forms the heart of the city's small business community.
Their trial has inspired one of the largest public shows of anger at the government in years and the largest outbreak of violence since Uzbekistan became an independent country after the 1991 Soviet collapse.
A representative of the Uzbek Islamic Liberation Party, Hassan al-Hassan, speaking to Aljazeera from London, said that his party was not involved in the riots in Andijan.
Al-Hassan accused Washington of covering up what he called the crimes of Karimov.
"Thousands of detainees in prisons in Uzbekistan have been subjected to various forms of torture and inhuman treatment at the hands of state security forces," he said.