The UN's top human rights official has called for an independent investigation into reports that Uzbek troops shot dead hundreds of protesters.
The people of Andijan have been living under curfew
Louise Arbour, the UN High Commissioner for Human Rights, said she was "deeply concerned" about last week's violence.
The Uzbek government said 169 people died in the shootings, but a local army source told the BBC 500 were killed.
UK Foreign Secretary Jack Straw and the European Union have backed calls for an independent inquiry into the events.
Speaking in Washington, Mr Straw called on the Uzbek president to allow full access to Andijan, where the killings took place, to enable a "credible and transparent investigation".
Mr Straw said action needed to be taken to tackle what he called "the root causes of the discontent" and "develop a much more open and pluralistic society in Uzbekistan".
Foreign diplomats visited Andijan on Wednesday, but were not allowed to speak to locals.
The unrest began when a group of men stormed the town's prison and freed 23 businessmen accused of being Islamic extremists. These men joined a large protest which correspondents say was also fuelled by long-term frustration over poverty and unemployment.
Locals say troops then fired indiscriminately into the crowd. The authorities say no civilians were killed, only Islamic militants who had organised the protest.
Diplomats and journalists who were allowed to see Andijan on Wednesday were taken on a tightly controlled tour that illustrated the government's version of Friday's events, correspondents present said.
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
"They weren't letting people get anywhere near us and there were no cars on the street either. We hardly saw any people at all," said Bakhtior Imamov of the BBC's Uzbek service.
The visitors saw an army base where they were told a "criminal gang" stole weapons, and a prison which the protesters broke open.
Uzbek Interior Minister Zakir Almatov, making a rare appearance, said the authorities had now named the man they believe was behind Andijan's violence as Qabuljan Parpiev.
He gave no information about who Mr Parpiev is, or whether he is alive or dead.
In the nearby border town of Korasuv, where local people seized control following the violence, a man apparently in charge of the uprising told the BBC that residents wanted to establish an Islamic administration and were willing to fight for their freedom.
Bakhtior Rakhimov said the people in the region had put up with Uzbek President Islam Karimov for 16 years, and could no longer tolerate him.
Washington has been under pressure to take a tough line against the repressive Uzbek regime, which is a key US ally in Central Asia.
On Tuesday, US Secretary of State Condoleezza Rice said Uzbekistan needed "openness" and "reform".