The African Union said on Thursday it had suspended Sudan until a civilian government was formed, intensifying international pressure on the country's new military rulers to give up power, Reuters reports.
Ethiopia meanwhile will launch a mediation effort on Friday, diplomatic sources in Khartoum said.
The moves take place after security forces cleared protesters from a sit-in camp in central Khartoum on Monday, killing dozens of people in the worst violence since President Omar al-Bashir was removed by the military in April after four months of generally peaceful protests.
The opposition had been in talks with an interim military council over a civilian-led transition to democracy, but the negotiations faltered and this week's crackdown marked a turning point in the power struggle.
The United Nations and several foreign governments have condemned the bloodshed.
The African Union's Peace and Security Council, in a meeting in Addis Ababa on Thursday, decided to suspend Sudan from all AU activities until a civilian government has been formed. Suspension is the African Union's normal response to any interruption of constitutional rule in one of its members.
Ethiopian Prime Minister Abiy Ahmed was due to visit Khartoum on Friday to try to mediate between the military and an opposition alliance, a diplomatic source at the Ethiopian embassy in Khartoum said.
The source told Reuters that Abiy would meet members of the Transitional Military Council and the opposition's Declaration of Freedom and Change Forces during his one-day visit.
Ethiopia hosts the headquarters of the African Union but it was not clear if Abiy would be acting under AU auspices.