Rattled recent arrivals at a 92,000-person makeshift camp here at Mauritania’s remote eastern edge describe an influx of jihadists — some homegrown and others possibly from afar — intent on imposing an Islam of lash and gun on Malian Muslims who have long coexisted with Western tourists in the fabled town of Timbuktu.

The conditions here in Mbera are grim, with many of the Malians sick, hungry and bewildered. But that is better, refugees said in interviews Tuesday, than the grueling life turned upside-down that an unexpected Islamist military triumph inflicted on their lives in a vast region in the heart of West Africa.

Refugees from such places as Timbuktu, Goundam, Gao and Kidal described witnessing repeated whippings, beatings and other punishments in the streets, ostensibly for having violated strict Islamic law, and some of those who fled said they had been subjected to this harsh justice themselves.

“They said: ‘You are thieves. Why are you out walking at this hour?’ ” Mohamed ag el-Hadj, a 27-year-old former soldier in the Malian Army recalled. He and a friend out for a stroll at 7 in the evening found themselves surrounded by two carloads of well-armed men. The men tied the friends’ arms behind their backs, bound them to a tree and forced them to kneel, bending forward, for the evening. In the morning, “everything was swollen.”

“It was scary,” Mr. Hadj recalled. “They insulted me, called me a savage, an unbeliever.”