"Shame on Egypt," thundered the headline in the Al-Arabi newspaper on Sunday, as relatives held funerals across Cairo for the dead, who included women and children.
"Prosecute the murderers and dismiss the minister of interior," the paper demanded.
Thousands of riot police wielding sticks and water cannon forcibly removed hundreds of Sudanese demonstrators, in an operation that began at dawn on Friday.
The independent Al-Isboa newspaper called it "the night the human conscience was lost".
"The interior ministry lost its mind and killed 20 Sudanese in the Mohandiseen massacre," declared Sawt al-Umma, referring to the upmarket Cairo neighbourhood where up to 2000 refugees had been camping outside UN offices to draw attention to their cause.
The semi-official press carried statements by officials defending the action, which they insisted came after repeated demands by the UN refugee agency.
Relatives were combing the city's hospitals and mortuaries on Sunday to find missing loved ones, as the government has not publicised information on the locations of the dead and injured.
Police used water cannon and
sticks to break up the protest
The international community, led by Kofi Annan, the UN secretary-general, and the United States, voiced its concern at the violence, and the New York-based Human Rights Watch called for those behind the deaths to be punished.
The Cairo church where many Sudanese Christians pray plans a memorial over the next few days.