International efforts to end the crisis in Egypt are gaining momentum as diplomats from the Gulf, the EU and the US have met the deputy leader of the Muslim Brotherhood, Khairat el-Shater, who is currently in jail.
Sources told Al Jazeera's Jamal al-Shayyal that Shater met the diplomats face-to-face but refused to negotiate with them, insisting that the delegation meet ousted president Mohamed Morsi instead.
Shayyal, reporting from Nasr City in Cairo, said that this is "a hugely significant development on the political and diplomatic front".
Shater met the foreign ministers of Qatar and the United Arab Emirates, as well as US Deputy Secretary of State William Burns and the European Union representative to the Middle East.
"We understand the meeting lasted just under an hour, and in that meeting Shater told the delegates they should not be wasting their time negotiating with him, and that Egypt has a president, and his name is Mohamed Morsi," Shayyal said.
Shater is an influential Muslim Brotherhood leader who is currently facing charges of inciting killings during protests a few days before the military toppled Morsi.
Meanwhile, the MENA agency cited an "informed source" as saying the envoys seeking to mediate an end to Egypt's crisis had received permission from the prosecutor-general to visit Shater.
The fresh mediation has been gathering pace at a time when the army-backed government says it will give mediation a chance.
To that end, US senators John McCain and Lindsey Graham arrived in Cairo on Monday as diplomatic efforts to end the country's political crisis intensify.
Burns, who has been holding parleys with Egyptian leaders, has extended his stay in Cairo for another day. He held talks with Adly Mansour, the country's interim president, on Sunday to find a way out of the crisis.
Brotherhood officials on trial
US officials have been grappling with how to respond to the situation in Egypt since Morsi was overthrown by the military on July 3, plunging the nation into turmoil.
"I want to keep the aid flowing to Egypt but it has to be with the understanding that Egypt is going to march towards democracy, not towards a military dictatorship. And that's the message we're going to send," Graham said.
Meanwhile on Sunday, the Cairo appeals court announced an August 25 date for the trial of six Brotherhood officials on charges of murder and incitement.
The defendants include the group's leader, Mohamed Badie. The group is accused of inciting clashes outside their headquarters on June 30, which left at least 12 people dead.
Prosecutors also ordered Morsi's top aide, Rifaa Tehtawi, held for 15 days pending an investigation into charges connected to last December's clashes at the presidential palace.
Tehtawi was detained last month along with the former president.
Protests against the army-backed ouster of Morsi, meanwhile, continue in Cairo and elsewhere, with an "anti-coup alliance", led by the Muslim Brotherhood, demanding that Morsi be released immediately.