Sudan summoned the Egyptian ambassador over the arrest of a Sudanese student in Cairo.
Waleed Abdelrahman is said to have taken part in anti-government protests in Egypt, but his family has denied the allegations.
After the meeting the envoy said Sudanese diplomats would be able to meet him on Sunday.
Hundreds of people demonstrated outside the foreign ministry in Sudan’s capital, Khartoum, to demand the release of the student.
The protests against President Abdel Fattah el-Sisi, the first in a long time, erupted last week.