CAIRO — Egyptian police detained two leaders of a Muslim Brotherhood-allied party in the latest in a wave of arrests of prominent Islamists following President Mohammed Morsi's ouster, while Europe's top diplomat held talks with the rival sides Monday to try to mediate an end to the country's increasingly bloody crisis.
It was European Union foreign policy chief Catherine Ashton's second visit to Cairo since Morsi was toppled nearly a month ago, underscoring the urgency felt after violence that has killed more than 260 people and all but dashed hopes of political reconciliation in the deeply divided country.
International concern has spiked after security forces killed at least 83 Morsi supporters in clashes outside their sit-in where they have been calling for his reinstatement in Cairo over the weekend. Human Rights Watch and field doctors interviewed by The Associated Press said many were killed by gunshots to the head and chest.
Security officials said Monday that a police captain died of wounds sustained during those clashes after being hit in the eye with birdshot from protesters. The officials spoke on condition of anonymity because they were not authorized to brief the media.
The clashes, which the Brotherhood has described as a "massacre," came after millions took the streets to show their support for military chief Gen. Abdel-Fattah el-Sissi. The mass turnout followed a call from el-Sissi, who also is defense minister, for rallies to give him a mandate to deal with violence and "potential terrorism" — a thinly veiled reference to expected crackdowns on Morsi supporters who are holding sit-in camps in Cairo.
The military pushed Morsi from power after days of mass protests by millions of Egyptians demanding that the president step down after a year in office.
The Muslim Brotherhood denounces the coup and has vowed to keep up its rallies until Morsi is reinstated.
"The military coup is the highest level of violence and terrorism to millions of Egyptians who voted in free elections, in addition to the preference of parties and bias against others," top Brotherhood official Essam El-Erian wrote Monday in a statement on his Facebook page.
The group has called for rallies outside security facilities on Monday evening during which they plan to carry empty coffins as a symbol of their dead. They have also called for mass protests Tuesday under the banner "Martyrs of the Coup," and have set up a tent a block away from their main sit-in for prayers for those killed over the weekend.
The Interior Ministry has vowed to take decisive action against anyone who violates state property, referring to the protesters efforts to expand their encampment.
Egypt's authorities have rounded up several Brotherhood leaders and other prominent Islamists since Morsi's ouster. The circle of those in custody expanded late Sunday after authorities arrested two figures from the Brotherhood-allied Wasat Party and took them to the capital's Tora prison.
Security officials said that Abul-Ela Madi and Essam Soltan, who faced arrest warrants linked to allegations of inciting violence, were found hiding in a home in a Cairo neighborhood located near the main protest site of Morsi's supporters.
The party condemned the arrest of its leaders, saying such measures exacerbate the crisis and add new obstacles to efforts to build bridges.
Morsi himself has been held incommunicado by the military since his ouster. Last week prosecutors announced they had launched an investigation into the ousted president on charges of murder and conspiring with the Palestinian militant group Hamas to carry out an attack on a prison during the 2011 uprising against autocrat Hosni Mubarak. The jailbreak allegedly led to the deaths of inmates and broke Morsi and around 30 other members of the group out of detention.
The president's spokesman Ahmed el-Musalamani said "Morsi is not a political prisoner" and prosecutors and the judiciary is looking into the charges against him.
In a bid to try and mediate a solution to the crisis, the EU's Ashton has planned meetings with both sides Monday. She met with el-Sissi, Foreign Minister Nabil Fahmy as well as Vice President Mohamed ElBaradei. Her office said in a statement she was also to meet with interim President Adly Mansour.
The Brotherhood's political wing says four of its members and Morsi's ex-prime minister, Hesham Kandil, are holding talks with Ashton as well.
While the Brotherhood and its Islamist allies have rejected the new political order, the military-backed interim leadership is pushing ahead with a fast-track transition plan to return to a democratically elected government by early next year.
In a statement before arriving to Cairo, Ashton said she is going to speak to all sides to reinforce that "there must be a fully inclusive transition process, taking in all political groups, including the Muslim Brotherhood."
"I will also repeat my call to end all violence. I deeply deplore the loss of life," she said.
The Egyptian presidency said the vice president received a call from U.N. Secretary-General Ban-Ki moon Monday urging an end to violence and a roadmap that includes the political participation of all parties.
Divisions between pro and anti-Morsi camps have played out in nearly daily street battles, with a dozen homes catching fire in Cairo late Sunday. Security officials said that no one was injured when the ousted president's supporters threw firebombs from atop a main overpass onto homes and opponents below.
Security officials said Monday that 11 bodies with signs of torture have been found in areas around the two pro-Morsi sit-ins in Cairo. Another 10 people have reported being tortured and accused of being spies by the protesters there. All officials spoke anonymously because they were not authorized to speak to the media.
Separately, a man who appeared to be a pro-Morsi supporter was killed when his store was burnt by a mob in the city of Port Said on Sunday. It was the third death in Port Said that day. Earlier, two people died when fighting broke out at a funeral for one of the 83 killed in clashes with police in Cairo.
Associated Press writer Maggie Michael contributed to this report.