Egyptian police fired tear gas at students protesting the Wednesday morning arrest of a key Muslim Brotherhood figure, who had been on the run since the July coup that ousted the country's Islamist president.
Students at al-Azhar university have been demonstrating for weeks in support of ousted President Mohammed Morsi, who was ousted by the army in July after mass protests against his rule, Reuters reported.
According to an interior ministry statement, the head of the university had called on the police to enter campus grounds to "protect souls and properties."
The arrest of Essam el-Erian, the deputy leader of the Brotherhood's political arm, the Freedom and Justice party, was the latest in a wide-ranging crackdown and prosecution of both the Islamist group's leaders and its rank-and-file since Morsi's ouster.
Morsi himself is in detention, held incommunicado at an undisclosed location and is due to appear in court on Nov. 4 on charges of inciting followers to violence and murder.
El-Erian was apprehended by security forces acting on a tip that led them to the apartment in the suburb of New Cairo, a security official said, speaking on condition of anonymity because he was not authorized to talk to the media.
The media-savvy el-Erian was among few senior Brotherhood figures still on the run. He was considered a more moderate leader, but turned hard-line and went into hiding after the July 3 coup that ousted Morsi, Egypt's first freely elected president.
Following Morsi's ouster, the country's new, military-backed authorities cracked down on the group, arresting hundreds of Brotherhood figures and putting top leaders on trial. The authorities are seeking through the prosecutions to show that the Brotherhood fueled violence during Morsi's one-year presidency and after the coup -- and to give legal justification for imprisoning its leaders.
Amid the violence surrounding the crackdown and a wave of arrests of thousands of Brotherhood supporters, calls for reconciliation that would return the group -- which dominated elections after the 2011 fall of Hosni Mubarak -- back into the political system have gone nowhere, with neither side giving ground.
From hiding, el-Erian had distributed messages to followers, urging them to denounce the coup and demand Morsi's reinstatement. In a recent pre-recorded message aired on the pan-Arab Al-Jazeera network, el-Erian criticized the military and the interim authorities and called on supporters, including students, to keep up their protests.
El-Erian's arrest came just hours after three judges presiding over a trial of nearly three dozen Brotherhood members, including its top spiritual leader and its chief financier, stepped down on Tuesday after security agencies refused to let the defendants attend the courtroom sessions.
The move was a sharp pushback from within the establishment over the conduct of the trial amid criticism by the Brotherhood that wide-ranging prosecutions of its leaders, including Morsi and the group's spiritual guide, Mohammed Badie, are only vengeful show trials.
The Brotherhood and allied Islamists reject Egypt's new government, insisting that Morsi be reinstated in office. They have continued protests, often leading to clashes with security forces that have killed more than 1,000 people. The Brotherhood says its protests are peaceful, but authorities accuse them of attacking security forces and provoking violence.
The Associated Press contributed to this report.