One of the Black Bloc groups in Cairo claims responsibility for attacking the Muslim Brotherhood office in Manial district during the 'Friday of Restoring Dignity' demonstrations.
In their statement issued on Sunday, Black Bloc Cairo also dismisses allegations by the Islamist group that they assaulted women in the process.
In fact, they assert: "We refrained from setting the office on fire for fear that women inside would have been harmed."
The group did make it clear that it carried out the assault "individually and did not orchestrate it."
Black Bloc is a radical opposition group whose members dress in black and conceal their faces. It made its first appearance on the eve of the second anniversary of the January 25 Revolution with a primary aim of fighting the Muslim Brotherhood.
Angry protesters stormed a number of the Islamist group's offices on Friday, including in Mahalla (Gharbiya governorate), where protesters threw Molotov cocktails and set alight an office of the Brotherhood's political wing, the Freedom and Justice Party (FJP), while chanting against the group and the president.
In Zagazig (Sharqiya governorate) angry protesters stoned a local Brotherhood office.
On the Mediterranean coast in Egypt's second-largest city, Alexandria, protesters ransacked a local FJP office.
The call to protest was prompted after Muslim Brotherhood members and guards allegedly attacked a group of anti-Brotherhood protesters, journalists and graffiti artists outside the Islamist group's headquarters on Saturday, 16 March.