US senators urge Egypt to free political prisoners
Two leading US senators have urged Egypt's military-backed interim government to release all political prisoners during a visit to Cairo.
John McCain and Lindsey Graham also called for a national dialogue that included the Muslim Brotherhood of ousted President Mohammed Morsi.
Earlier, they met senior officials as part of a US diplomatic push to help end the political crisis in Egypt.
More than 250 people have been killed since Mr Morsi was deposed on 3 July.
Mr Morsi and several other prominent Brotherhood figures are currently being detained on suspicion of various offences.
Thousands of their supporters have taken to the streets to demand the reinstatement of Egypt's first democratically elected president, something the interim authorities have insisted will not happen.
The government has promised to break up mass sit-ins by Morsi supporters outside the Rabaa al-Adawiya mosque in the suburb of Nasr City, and in Nahda Square, near Cairo University in Giza, to the west.
The two Republican senators arrived in Cairo on Monday evening at the request of US President Barack Obama in an effort to defuse the crisis.
On Tuesday, they attended talks with interim Vice-President Mohamed ElBaradei, Prime Minister Hazem Beblawi, and the head of the armed forces, Gen Abdul Fattah al-Sisi.
The Mena state news agency reported that the general had discussed with them how to bring an end to "the state of political polarisation and stop the violence".
They also met members of the Brotherhood's political wing, the Freedom and Justice Party (FJP).
Referring to the overthrow of Mr Morsi as a "coup" - a word the Obama administration has chosen not to use - the senators warned that "inclusive democracy" was "the only viable path to stability".
"The people who are in charge were not elected. The people who were elected are in jail. The status quo is not acceptable," Senator Graham said.
"In democracy, you sit down and talk to each other. It is impossible to talk to somebody who is in jail," he added.
Senator McCain warned: "What happens in Egypt in the coming weeks is very critical and will have a decisive impact on this country, but also on the broader Middle East."
"We have urged the release of political prisoners. We have urged a national dialogue that is inclusive of all parties that renounce the use of violence. We have strongly urged a set timetable for amendment of the constitution, elections for the parliament, followed by elections for the presidency."
The senators stressed that they had no intention of taking part in any negotiations themselves.
Later, interim President Adly Mansour appeared to reject their efforts.
A spokesman, Ahmed al-Musalamani, told reporters that "foreign pressure" had "exceeded international standards". He also said the authorities would protect "the revolution".
Earlier this week, there were reports that the interim government was prepared to release leaders of the Muslim Brotherhood from custody and offer the group ministerial positions if they called an end to the sit-ins. However, a presidential adviser denied such an offer had been made.