Airport sources said police had put the Eritreans on an EgyptAir plane for Asmara and had handed them over to EgyptAir security.
The Eritreans were caught on the Egyptian-Israeli border a few days ago while trying to slip across into Israel .
Hundreds of African migrants have attempted the journey in recent years. This year alone Egyptian police have shot and killed 28 of them and Egypt has deported up to 1,200.
The New York-based group Human Rights Watch said on Saturday that Egypt must not deport Eritrean asylum seekers without giving the office of the U.N. High Commissioner for Refugees ( UNHCR ) an opportunity to assess their claims.
It said that Egypt was holding around 98 Eritrean migrants in a detention centre in Sinai, and UNHCR had no access to them.
The London-based rights group Amnesty International said that in Eritrea the asylum seekers would probably be held incommunicado in inhumane conditions for long periods of time.
“Any member of the current group, if forcibly returned, could also face torture or other ill-treatment, particularly as many of them are believed to have left Eritrea to avoid forced conscription,” it added.
The UNHCR office in Cairo said it was investigating the report that Egypt had repatriated the Eritreans. “It seems that this is a group we did not know about,” said one official.