As numbers surged and fuel became scarce, prices of buses to Egypt rose to about $500 per person.
Those who can afford the trip are relatively wealthy, but many arrive through the Arqeen and Qustul crossings either side of Lake Nasser in a reduced state.
"There are merchants of the war who exploit the crisis to make profit," said Leem al-Sheikh, a 23-year-old dentist who took nearly a week to reach Abu Simbel from Omdurman.
"We are privileged," she added. "There are many who couldn't afford to flee the war."
One group of female and elderly relatives with children could be seen emerging onto Egyptian territory at Arqeen with faces and clothes covered with dust, dragging trolleys piled with bags before they boarded a bus for Cairo.
Since adult males need visas to enter Egypt, men generally lag behind. Many wait in Wadi Halfa in northern Sudan to apply for visas.
Some have complained of a lack of food, water, shelter and washrooms at the crossings. They say they have slept on buses or rubbish strewn roads, or inside a sealed zone between the two border posts.
Farid Mahgoub Taha, a 77-year-old who fled from Khartoum, said he had found a "very dire" situation at Arqeen, thought services were better on the Egyptian side.
"It was not suitable for humans, not even animals," he said.
Sheikh said that people were subjected to lengthy and aggressive questioning by Egyptian officials.
"They are humiliating us. They yell and say if you don't wait, we will send you away," she said.
An Egyptian border guard said staff were working around the clock to deal with the influx. Egypt's Foreign Ministry said authorities were providing relief and emergency services at the crossings and trying to speed up entry procedures by reinforcing border staff.
One Khartoum resident who gave only his first name, Khaled, said "I've seen a few fellow friends of mine who have already travelled. They're still in the border, stuck in the streets," he told Reuters on a video call. "I can't put my family through that."
