Troops in Uzbekistan have shut off the eastern border town of Korasuv, where locals seized control on Saturday.
Local people went on the rampage in Korasuv at the weekend
The unrest spread from nearby Andijan, where local sources said several hundred people died when troops opened fire at protesters on Friday.
Some refugees near Korasuv said troops shot at them as they tried to cross the border into Kyrgyzstan - and some died.
UK Foreign Minister Jack Straw said his Uzbek counterpart had pledged to allow diplomats access to Andijan on Tuesday.
At a news conference in London Mr Straw also he repeated his condemnation of Friday's events, telling reporters that the violence "cannot be justified".
Most populous central Asian former Soviet republic, home to 26m people
Ruled since 1991 independence by autocrat Islam Karimov
Accused by human rights groups of serious abuses, including torture
Rocked by violence in capital Tashkent in 2004
Government says radical Islamic groups behind violence
Uzbek President Islam Karimov said 10 soldiers and "many more" protesters were killed in Andijan, and blamed the unrest on Islamic extremists.
The protests were sparked by a long-running trial of local businessmen accused of Islamic extremism. Their families say they are innocent and have been unfairly targeted.
There is also long-term pent-up anger in Uzbekistan regarding poverty, unemployment and other social problems, observers say.
On Saturday, as news of the violence in Andijan filtered into Korasuv, residents went to the mayor demanding that a border crossing to the Kyrgyz side of the town, shut by the authorities two years ago, be reopened.
Correspondents say locals saw the closed border as an attempt to grind them down by denying them access to the thriving market on the other side.
When the mayor refused, he was beaten. Angry crowds set fire to the militia headquarters, the road police and the tax inspector's office - the three most visible representatives of the central government.
Uzbek troops have since rebuilt two bridges over the border, but have set up checkpoints on the roads leading into Korasuv.
Korasuv residents have been meeting to discuss how to run their own affairs. The town is currently calm, although there are rumours that the central authorities may move to take control, says the BBC's Ian MacWilliam in Kyrgyzstan.
He says the Korasuv unrest is exactly the kind of local rebellion the Uzbek government hoped to prevent by a show of force in Andijan.
A correspondent for the IWPR media development charity in Korasuv, Sultan Kanazarov, said although the town had been sealed off by a ring of troops, there was no great sense that it might come under attack.
Hundreds of people have fled over the Uzbek border towards Kyrgyzstan. It is not clear how many of them were involved in the Andijan demonstration.
A spokesman for the UN's refugee agency, Peter Kessler, said the authorities in Kyrgyzstan were preparing for large numbers of refugees from Uzbekistan.
He said several dozen of those that had already crossed the border were wounded.
One boy, 15-year-old Biloliddin, told the BBC he attended the Andijan demonstration but fled when the shooting began. He said refugees were fired at again when they tried to cross the border.
Andijan itself is reported to be quiet, with soldiers and tanks patrolling the streets.
But the BBC's Monica Whitlock, in Tashkent, says prices are rising fast in Andijan because roads into the town are blocked and traders are afraid to cross army checkpoints.
Since poverty was one of the chief reasons why so many people protested on Friday, this is a very important issue, our correspondent says.