CAIRO (AP) -- Egyptian prosecutors on Monday summoned several opposition politicians and activists for questioning over allegations they incited violence against members of the president's Muslim Brotherhood.
The summons came one day after the Islamist president sternly warned his opponents, saying he may be close to taking unspecified measures to "protect this nation."
Angry, shouting and pounding the table at times, Mohammed Morsi vowed to bring to account politicians found to have incited the violence on Friday, when Brotherhood members and protesters clashed outside the group's Cairo headquarters.
Nearly 200 people were injured in the clashes, the worst violence between the Brotherhood and its opponents in more than three months.
Those summoned include former presidential candidate Khaled Ali, former lawmaker Ziad el-Oleimi and several iconic figures from the pro-democracy movement behind the 2011 uprising against Hosni Mubarak. These include Alaa Abdel-Fattah, Nawara Negm, daughter of Egypt's best known satirical poet, and senior opposition politician Mohammed Aboul-Ghar.
The summons, based on complaints filed by injured Brotherhood members, are likely to stoke tensions and extend the latest in a series of political crises roiling the nation since Mubarak's ouster two years ago. Coupled with economic woes and tenuous security, the ongoing bout of turmoil is by the far the worst since 2011, with at least 70 people killed and hundreds injured in protests and clashes with police since late January.
Friday's violence was rooted in an incident a week earlier, when Brotherhood members beat up activists who were spray-painting graffiti against the group outside its headquarters, located in an eastern district of Cairo. In response, anti-Brotherhood activists called for a protest Friday outside the headquarters. Both sides brought out hundreds of supporters, and the scene quickly turned to mayhem, with members of each side seen beating the other.
In Sunday's address, Morsi, who took office in June as Egypt's first freely elected president, departed from prepared comments at a women's rights conference to deliver a scathing attack against his opponents. The president suggested that he may have to resort to "emergency" measures to deal with his opponents. He accused his foes of using paid thugs to sow chaos and the media of inciting violence.
He made no mention of any particular opposition group or politician and did not refer directly to Friday's calashes. However, his animated comments left little doubt that they were directed at the National Salvation front, the main opposition coalition, and former members of the Mubarak regime.
Alluding to Mubarak-era figures who have been acquitted in court of a range of charges, Morsi said he respected the law and judicial rulings, but added: "There is a president of the republic and there are emergency measures if any of them makes even the smallest of moves that undermines Egypt or the Egyptians."
"Their lives are worthless when it comes to the interests of Egypt and Egyptians," he said, pounding on the table. "I am a president after a revolution, meaning that we can sacrifice a few so the country can move forward. It is absolutely no problem."
Morsi also criticized the media, arguing that it was being used for political aims. His attack on the media has been a popular refrain by the Brotherhood in recent weeks. Dozens of Islamists are currently staging a sit-in outside the studios of TV networks critical of the president.
The Islamists on Sunday pelted police with rocks, sought to prevent talk show hosts and guests from going in or out of the complex, located in a suburb west of the capital. Police used tear gas when pelted with rocks. The sit-in continued on Monday.