The interim government in the impoverished Central Asian nation ordered troops to shoot rioters dead but even that has failed to stop the spiralling violence which has left more than 100 people dead and over 1,100 wounded since Thursday night.
Doctors and rights activists say that official toll is far too low because wounded minority Uzbeks are too afraid of being attacked again to go to hospitals.
The riots are the worst violence since former president Kurmanbek Bakiyev was ousted in a bloody uprising in April and fled the country. The Uzbeks have backed the interim government, while many Kyrgyz in the south had support the toppled president.
Thousands of Uzbeks have fled in panic to the nearby border with Uzbekistan after their homes were torched by roving mobs of Kyrgyz men. Some Uzbek women and children were gunned down as they tried to escape, witnesses said.
Fires set by rioters have destroyed most of Osh, the country's second-largest city, and looters have stolen most of its food.
Triumphant crowds of Kyrgyz men took control of most of Osh on Sunday while the few Uzbeks still in the city of 250,000 barricaded themselves in their neighbourhoods.
The rampages spread quickly Sunday to Jalal-Abad, another major southern city, and its neighbouring villages, as mobs methodically set Uzbek houses, stores and cafés on fire. The rioters seized an armoured vehicle and automatic weapons at a local military unit and attacked police stations around the region trying to get more firearms.
Police and the military appeared to be on the defensive across the south, avoiding clashes with mobs.
Blames deposed president's family
Interim President Roza Otunbayeva blamed Bakiyev's family for instigating the unrest in Osh, saying it was aimed at derailing a constitutional referendum on June 27 and new elections scheduled for October.
A local official said Bakiyev supporters had attacked both Kyrgyz and Uzbeks to ignite the rioting. "Bakiyev's entourage has funded and organized these riots," Otunbayeva's deputy Omurbek Tekebayev told The Associated Press.
From his self-imposed exile in Belarus, Bakiyev issued a statement denying any role in the violence and blaming the interim authorities for failing to protect the population.