“It’s as if life has stopped in its tracks,” Mr. Stillhart said after his three-day visit to the area. Homes destroyed by fire observed along the road gave a clue to the scale of the destruction, he said. “And then there is this pervasive sense of absence,” he added.

A working estimate among relief agencies is that about 300,000 Muslims remain in Rakhine State in western Myanmar, including about 180,000 in the mainly Muslim north, but no one is moving around, he said.

Apart from being at a few checkpoints on the roads, soldiers and police officers are hardly visible, but villagers do not venture from their homes or the fields immediately adjoining them, Mr. Stillhart observed. Markets that were bustling with life before August are largely deserted, and most of the shops are closed.

About 300 Rohingya Muslims a day still cross the border from Rakhine State to Bangladesh, international relief agencies report, swelling a population of nearly 650,000 Rohingya Muslims who have fled since August. The refugees are cramming into squalid camps of improvised shelters that lack basic sanitation.

Aid agencies struggling to cope with high levels of malnutrition among children are now battling an outbreak of diphtheria, which the World Health Organization reported on Tuesday had struck more than 770 people and killed nine. But refugees who are able to communicate with those who remain in Rakhine State report that life in the camps offers greater security, Mr. Stillhart said.