The city of Osh, where mobs marauded for three days, was mostly quiet on Monday morning, and its government buildings appeared to be well protected.

But Kyrgyz volunteers armed with bats and iron bars — some recently arrived from the north of the country — continued to patrol outlying villages, saying they were defending the country’s south against an Uzbek attempt to seize it.

Thousands of people fleeing the violence massed at Nariman, on the border with Uzbekistan, where Dilmurad Failakov, a doctor from a local hospital, said four newborns had died on Monday morning and dysentery was spreading among the children. Refugees, who were mostly sitting on the ground, said they had seen truckloads of humanitarian aid passing by, but none of them had stopped.

The government of Uzbekistan estimated that 75,000 people were fleeing and said it had set up refugee camps on its side of the border.

Doctors in Nariman said they were scrambling to treat gunshot wounds and cases of dysentery under circumstances they described as desperate. There was no government presence at the growing camp, and Mr. Failakov, the doctor, said 10 of his patients had died because he had no access to medical supplies.

Roughly 70,000 refugees had crossed the border on Sunday, and about 1,000 were able to cross on Monday, said Akmal Khaidarov, another doctor at the site, who estimated that the number of Uzbeks crowding into the border village had grown to 5,000.

Occasional truckloads of people fleeing the violence continued to arrive, including a man who said he had been driving when a gunmen in a bus opened fire on his car, which flipped over as he tried to escape.

Families sat together in groups under a scattering of tents, and naked children played in the open air as Uzbek border guards in camouflage faced them from the other side of a barbed-wire barrier. Ethnic Uzbeks make up about 15 percent of the overall population of Kyrgyzstan, but they are represented in much higher numbers in Osh, which has roughly 225,000 people and is on the Uzbek border.