The United States has called on Egypt's military to free deposed president Mohamed Morsi.
State Department spokeswoman Jen Psaki said the United States backed Germany's earlier appeal for Morsi to be released.
The ousted Islamist-backed president has not been seen in public since his removal from office on July 3.
Officials have said Morsi was being held at a Republican Guard compound in Cairo.
Tens of thousands of supporters of Morsi protested in Cairo on July 12 to demand that he be reinstated.
Opponents of Morsi also staged rallies to mark the first weekend of the holy month of Ramadan.
The pro-Morsi Muslim Brotherhood has said it will not take part in a new military-backed interim government that is being assembled.
Based on reporting by Reuters and AFP