US ambassador to Egypt rushed to Germany from where she will return to United States, according to German news agency.
Earlier, around 100 protesters calling for an end to military rule in Egypt clashed with soldiers near the US embassy in Cairo.
Shouting "Down with military power!" the protesters lobbed stones at the soldiers, who responded by throwing them back and trying to disperse the crowd.
The soldiers then returned to their position, where they were joined by a group of civilians, who also threw stones at the protesters.
Earlier, two civilian groups, one of them demanding the expulsion of the US ambassador, had clashed in front of the embassy, hurling stones at each other.
After months of pressure from Washington, 13 foreign defendants accused of receiving illicit foreign funds to operate unlicensed NGOs, including six Americans, were allowed to leave the country after posting bail last week, sparking outrage in Egypt.
A travel ban was lifted after the trial judges recused themselves in the face of what they said was intervention by the authorities.
