Further talks are expected in Egypt on Monday night aimed at finding a peaceful solution to a standoff between the government and supporters of ousted president Mohammed Mursi.
Envoys from the United States and the European Union met government officials and members of the Muslim Brotherhood on Saturday.
Few official details have been given about the talks.
The BBC reports US Deputy Secretary of State William Burns has visited Muslim Brotherhood deputy head Khairat al-Shater in prison.
The foreign ministers of Qatar and the United Arab Emirates are also reported to have visited the Brotherhood's deputy leader.
Brotherhood spokesman Gehad al-Haddad said that Mr Shater had told Mr Burns that he was "no position to speak" and that the delegation should direct their questions to Mr Morsi.
Mr Shater also told the diplomats that Mr Morsi held the key to solving the crisis and that there was no alternative to constitutional legitimacy.
On Monday, EU envoy Bernardino Leon met Prime Minister Hazem Beblawi.
Senators John McCain and Lindsey Graham are due in Cairo from the United States later in the day.
Before leaving Washington, Senator Graham warned that the Egyptian military must back out of politics quickly or risk a cut of the $US1.5 billion aid that it receives from the United States each year.
The BBC reports there is mounting tension over plans to break up two mass sit-ins by Morsi loyalists in Cairo.
Morsi supporters and their families have been camping in Nahda Square and outside the Rabaa al-Adawiya mosque since the president was removed from office by the army on 3 July.
A government helicopter has dropped leaflets urging people to leave.
More than 100 Morsi supporters have also been killed in clashes with security forces.
