Unidentified attackers set fire to tents erected by protesters outside the High Court in downtown Cairo on Wednesday, state-run news agency MENA reported.
The court building has sustained serious damages over the past few hours, according to MENA.
Protesters had reportedly harassed employees as they headed to work Tuesday, accusing them and the entire judicial system of corruption.
State-run Al-Ahram newspaper said angry protesters had rallied earlier outside the court and pelted it with stones, smashing its glass front. Court employees turned five of the demonstrators in to police. One eyewitness alleged that it was court workers who set protesters' tents on fire.
Officials have repeatedly blamed recurring protest clashes and attacks since the revolution on unknown armed parties.
Protesters also closed Tahrir Square once again after opening it briefly on Wednesday morning, following large demonstrations demanding the retrial of former President Hosni Mubarak and the formation of a presidential council.
The protesters placed metal barricades outside the Egyptian Museum, the Arab League, and at the square entrances on Qasr al-Nil bridge, Qasr al-Ainy and Mohamed Mahmoud streets.
Edited translation from Al-Masry Al-Youm