A statement released by the office of interim President Adly Mansour blamed the Brotherhood for "the failure of these efforts and the later events and developments that might result," CBS News reported.
The statement charged the Muslim Brotherhood had made impossible demands, Ahram Online reported.
A government official said the Cabinet would issue a third appeal for Brotherhood sit-ins to end in Cairo and Giza, saying the demonstrations "have not met the standards of peaceful marchers and sit-ins."
Ahmed Diyah, a Brotherhood member and spokesman for the National Coalition for Legitimacy, rejected responsibility for the talks' failure.
"We were open to a deal that would have recognized legitimacy," he said.
Diyah added the sit-ins "would not be ordered to disperse" because they "reflect the will to re-establish the legitimacy of the president and the constitution."
Tens of thousands of Morsi supporters have been defying government warnings to abandon two massive sit-ins in Cairo squares. The protesters are demanding the ousted president's reinstatement.
Soldiers and police have killed more than 140 Morsi supporters and wounded hundreds more. In addition, a growing number of Islamist leaders have been detained, some slapped with criminal charges they say are politicized.
If the crisis talks break down, Western governments have said they fear Egypt's security services will try to clear the pro-Morsi protesters, leading to a potential bloodbath.
Mansour's statement appeared hours after U.S. Sen. John McCain -- one of two senior U.S. senators in Cairo on a White House-requested mediation mission -- said he considered Morsi's removal a military coup.
"We have said we share the democratic aspirations and the criticisms of the Morsi government that led millions of Egyptians into the streets," the Arizona Republican told reporters.
"We've also said the circumstances of the former government's president's removal were a coup, and we have said that we cannot expect Egypt or any other country to abide by its laws if we do not abide by ours in the United States," he said.
Calling the ouster a coup would require Washington by law to suspend its annual $1.5 billion aid package, a move U.S. officials say would further destabilize Egypt. The Obama administration has declined to refer to the ouster as a coup.
McCain's remarks, during a visit with Sen. Lindsey Graham, R-S.C., drew a harsh response from Mansour's office.
"John McCain is distorting facts. His clumsy statements are unacceptable in form and substance," presidential aide Ahmed al-Muslimani told al-Ahram's Arabic website Monday evening.
State television said Mansour called McCain's comments "an unacceptable interference in internal policies."
The Egyptian Foreign Ministry planned an official response, Egypt's state-run Middle East News Agency said.
McCain is the first U.S. official visiting Egypt to refer to Morsi's removal as a coup. U.S. Secretary of State John Kerry said last week Egypt's military leaders were "restoring democracy" to the country and last month said the country might have avoided a civil war by removing Egypt's first elected president.
McCain and Graham have argued publicly Washington should call the ouster a coup even if the overthrow did follow huge street protests.
The senators have said they are not speaking for the administration.
McCain and Graham called on civil-disobedient Islamists to renounce violence. But they also called for the swift release of the detained Brotherhood officials so they could rejoin the political process.
"We are hoping and begging and pleading with the people of Egypt that they will look forward and not backward; that means releasing people so that they can negotiate," Graham said, adding, "It is impossible to talk to somebody who's in jail."
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