Soldiers in tanks are patrolling the streets of Osh in southern Kyrgystan.
At least 170 people have been killed since the worst violence between Kyrgyz and ethnic Uzbeks for 20 years erupted last Thursday.
The UN says eyewitnesses claim the violence was orchestrated by groups of armed men – and describes the region as a “powder keg”.
The interim government has been urged to contain the disorder and prevent it spreading throughout the Central Asian region.
But the authorities in Bishkek say the region’s main security bloc, a Russian-led group of ex-Soviet states, is unlikely to despatch a peacekeeping force immediately.
An estimated 100 thousand minority Uzbeks have massed on the border and in hastily-built refugee camps in neighbouring Uzbekistan.
The UN is calling for a humanitarian corridor to be set up urgently to help the vulnerable to safety and deliver humanitarian aid.
More than 200 tonnes of supplies are due to arrive in the region tomorrow.