Egypt says foreign mediation has failed to resolve crisis
International efforts to resolve the political crisis which followed the ousting of Mohammed Morsi have failed, Egypt's interim presidency says.
Interim head of state Adly Mansour and his backers in the military have been talking to diplomats from the US, EU, Qatar and the United Arab Emirates.
More than 250 people have been killed in political unrest since Mr Morsi was ousted on 3 July after street protests.
The interim PM urged Morsi supporters to end protests and disperse.
The government's decision to break up the protest camps led by the Muslim Brotherhood was "final and irreversible" and it had all but run out of patience, said Hazem Beblawi in a televised statement.
Any use of weapons against police would meet "utmost force and decisiveness," he was quoted as saying.
The Egyptian presidency declared in a statement that the "phase of diplomatic efforts has ended today".
"These efforts have not achieved the hoped-for results," said the statement.
The presidency said it "holds the Muslim Brotherhood completely responsible for the failure of these efforts, and for consequent events and developments relating to violations of the law and endangering public safety".
Interim authorities have repeatedly asked Brotherhood supporters to end two major sit-ins in Cairo. Diplomats have voiced concerns about the possible use of force to break up the protests.
Wednesday's statement said there was "full Egyptian government support" for the move to end the sit-ins peacefully, the BBC's Caroline Wyatt in Cairo notes.
But the sit-ins have lasted five weeks and the statement leaves people uncertain as to what will happen next, our correspondent adds.
The government statement came hours after US Deputy Secretary of State William Burns left Egypt following several days of mediation talks. He was assisted by the EU envoy, Bernardino Leon.
A joint US-EU statement issued on Wednesday called for a peaceful resolution of the conflict and expressed concern that the sides had not yet found a way to "break the dangerous stalemate"
It said the US and EU remained "ready to help in any way we can".
Separately, US state department spokeswoman Jen Psaki said "we believe that any solution will require both sides to make compromises."
Later, Mr Mansour said in a televised statement that his government had given diplomatic efforts every chance.
"We have given the time needed to exhaust the necessary efforts to curb the violence, end the bloodshed and stop the confusion in Egypt's society. I would like to tell you honestly that these efforts have not achieved the success hoped for, " he said in his speech to mark the end of the fasting month of Ramadan.
Clashes between Mr Morsi's supporters and residents in the city of Alexandria have left one person dead and dozens wounded, the Associated Press news agency reported.
Supporters of the former president have held daily street protests in Cairo and other cities.
Mr Morsi has been detained since he was deposed early last month. His whereabouts are not known. But the EU foreign affairs chief Catherine Ashton visited him last week and said he was "safe".
In their talks with Egyptian officials on Tuesday, the US Republican senators John McCain and Lindsay Graham called for the release of political prisoners and negotiations between the Muslim Brotherhood - which Mr Morsi belongs to - and the authorities.
"Democracy is the only viable path to stability," said Mr McCain. He called for "an inclusive political process in which all Egyptians are free to participate".