Germany and the United States called on Friday for Egypt to release President Mohamed Morsi from detention.
Mr Morsi, who was deposed last Wednesday by the army, is being held at an unspecified location.
The BBC reports dozens of people have since died in clashes during demonstrations by pro- and anti-Morsi protesters.
Mr Morsi's supporters gathered in the east of the capital, Cairo, on Friday - the first Friday of the fasting month of Ramadan - demanding his reinstatement.
Anti-Morsi protesters, whose demonstrations led to his removal a few days after the first anniversary of his election to office, gathered in smaller numbers in Tahrir Square.
Germany's foreign ministry urged the army to end restrictions on Mr Morsi and allow an international organisation, such as the Red Cross, access to him.
On Thursday, Washington urged Egypt to stop the "arbitrary" arrests of members of the Muslim Brotherhood.
However, the White House does not believe the administration should immediately suspend aid to Egypt.
The BBC reports the United States is due to send four F-16 fighter jets to Egypt, but has not publicly confirmed that the delivery will go ahead.
Week of protests
The BBC reports Mr Morsi's supporters staged mass protests throughout the week near the Presidential Guard barracks in eastern Cairo, where they believe he is being held.
The focal point of the protest is the Rabaa al-Adawiya Mosque, where they are camping around the clock.
Mr Morsi was removed on 3 July following nationwide protests by millions of people. Interim president Adly Mansour was installed in his place.
On Monday, 51 Morsi loyalists were killed by the army.
Mr Mansour has set a timetable for a new constitution and elections, but Mr Morsi's supporters have rejected the plan.
Hazem al-Beblawi, who was appointed as prime minister on Tuesday by Mr Mansour, said he could offer cabinet posts to the Freedom and Justice Party, the political wing of the Muslim Brotherhood. The FJP rejected the offer.