Egyptian state television said the interim prime minister had not yet been chosen, after named officials and state media earlier said Mohamed ElBaradei would be appointed on Saturday.
The report followed Egypt's second biggest Islamist group, which had initially backed a military-led political roadmap to guide the country to new elections, opposing the nomination of liberal politician ElBaradei.
The military ousted Islamist leader Mohamed Morsy on Wednesday, and his Muslim Brotherhood movement has led protests in which dozens of people have been killed.
