Aid workers are unable to obtain visas to get into Sudan or find safe routes to deliver food by road. The prices of food, water and fuel have skyrocketed, and many people are unable to access cash.

On Monday, the army was accused by the government of the Democratic Republic of Congo of bombarding a university in Khartoum on Sunday, killing 10 Congolese citizens. A spokesman for the army did not reply to an immediate request for comment.

In El Geneina, one Sudanese doctor who had been sheltering with a colleague in a medical guesthouse in late April said armed gunmen beat and robbed them before depositing them in the streets.

“The roads were filled with the smell of death and gunfire,” said the doctor, 30, who asked to be called by his nickname, Yousef, for security concerns. “Bodies were decomposing in the streets, covered in bullet wounds.”

He and his colleague lived on the run for the next month, he said, dodging gunfire and roving militias on motorbikes to reach a string of temporary shelters: a mosque, an abandoned clinic, a scorched market.