Escalating ethnic violence in Kyrgyzstan has prompted tens of thousands of ethnic Uzbeks to flee the country.
A third day of fighting in the south of the country has claimed nearly 100 lives, officials say.
Witnesses speak of Kyrgyz men shooting ethnic Uzbeks and setting property alight; a BBC correspondent in the city of Osh has heard heavy gunfire.
On Saturday the interim government gave security forces shoot-to-kill powers.
Kyrgyzstan's interim government has urged Russia to send in troops to help quell the violence, but Moscow says it has no plans to intervene.
A battalion of paratroops would be sent to protect Russian facilities in the country, Interfax news agency reported, quoting a security source.
Both Russia and the United States have military bases in the north of the country.
Kyrgyzstan's interim government extended a state of emergency to cover the entire southern Jalalabad region, as ethnic clashes spread there from neighbouring Osh.
One resident in Jalalabad said fighting was going on throughout the city.
"At the current moment, there are shoot-outs going on in the streets," he told the AFP news agency by telephone.
"There is a veil of smoke covering the whole city," another resident told AFP. He said buildings on fire included a shopping centre.
Without international assistance there are fears the interim authorities will struggle to contain the conflict, the BBC's Rayhan Demytrie in Osh reports.
She says buildings are ablaze in Osh - television pictures show street after street of burnt-out buildings and black smoke billowing in the air.
President Kurmanbek Bakiyev, who was ousted in April and now lives in Belarus, has denied accusations from the government that he is involved in the unrest in order to derail a 27 June constitutional referendum and elections scheduled for October.
Mr Bakiyev had strong support in southern Kyrgyzstan.
'We need food'
The south of Kyrgyzstan, an ex-Soviet Central Asian state of 5.5 million people, is home to an ethnic Uzbek minority of almost one million.
The violence has prompted tens of thousands of people to head for the nearby border with Uzbekistan.
Uzbek emergency officials said at least 30,000 people had crossed the border from Kyrgyzstan. One official told Russia's RIA Novosti news agency that 75,000 had entered Uzbekistan.
The International Committee of the Red Cross said it had received similar reports.
Ethnic Uzbek eyewitnesses told our correspondent at a border crossing with Uzbekistan that gangs of armed Kyrgyz had been marauding through neighbourhoods, killing residents and burning homes.
One woman pleaded for help: "We need food, we need water, I have got two sons and they are little and I need water and food to survive."
There have also been reports of Kyrgyz casualties.
One Kyrgyz family the BBC spoke to by telephone said an Uzbek boy armed with a gun shot dead three Kyrgyz men who were approaching them.
Pakistan says one of its citizens, a student, has been killed in Osh and it is investigating reports that 15 others have been taken hostage.
More than 1,000 people have been wounded in the violence, the authorities say. Some reports say the casualty figures could be much higher.
It is not clear what sparked the latest unrest.
According to local reports, fighting broke out between rival gangs and developed into gun battles late on Thursday.
In recent weeks, several incidents had prompted fears of inter-ethnic violence between Uzbeks and Kyrgyz.
The clashes are the worst ethnic violence to hit southern Kyrgyzstan since 1990, when several hundred people were killed. Kyrgyzstan was then part of the Soviet Union, which sent in troops to quell the unrest.