By Martin Plaut
BBC African analyst
The Sudanese had been camped outside the offices of the United Nations refugee agency in Cairo for three months before the Egyptian police dispersed them.
They hope to be resettled to other countries.
Some of the protesters have been waiting years to go to the West
But the UNHCR says it has no power to offer them what they want.
"We don't have a country that will take them," a UNHCR official said.
The trouble has been building up for a long time.
Three million Sudanese are in Egypt, many of them from troubled southern Sudan that has seen decades of civil war.
And over the years the UNHCR was able to find many new homes in Europe, the United States or other friendly countries.
Around 16,000 were resettled in the last 10 years.
But now the situation has changed. In January this year a peace agreement was signed between Khartoum and southern Sudan.
The sympathy of the international community has waned.
Southern Sudan remains poor after 21 years of war
Now, it is argued, the refugees can go home.
But many have waited years to get to the West.
They argue they are discriminated against, and have little opportunity to earn decent wages in Egypt as they wait to find new homes.
The UNHCR points out that Egypt seldom deports them, and offers some education and health care.
This has done little to placate the Sudanese and this frustration has now boiled over.