Offices of the Muslim Brotherhood’s Freedom and Justice Party (FJP) in different Egyptian governorates were reportedly raided and torched on Friday.
In the Nile Delta governorate of Daqahliya, the FJP's office was set on fire by protesters after the latter claimed to have heard shotguns being discharged from the building, eyewitnesses told Al-Ahram's Arabic-language news website.
The office remains besieged by thousands of protesters.
Eyewitnesses also told Al-Ahram that the number of injured were estimated at ten, including four who had since been transferred to hospital.
The Muslim Brotherhood, for its part, released a statement holding members of the anti-Morsi 'Rebel' campaign responsible for the violence.
Meanwhile, in Alexandria, which has seen clashes between the two rival camps since Friday afternoon, the FJP's office in the coastal city's Sidi Gaber district was set on fire.
The clashes in Alexandria have left over 40 injured, according to Ahram Online's Sayyed Gamal.
A Muslim Brotherhood office was also reportedly attacked in the Nile Delta Beheira governorate.
In a statement issued by Ikhwan Online, the Brotherhood's official website, the group accused former regime elements and members of the 'Rebel' campaign – who they called "thugs" – of being behind the attack in Beheira.
"The attackers looted the office," the statement read. "Although the party's young cadres appealed for help, police have refused to intervene."
The Nile Delta Gharbiya and Kafr Al-Sheikh governorates, meanwhile, also witnessed attacks on the Islamist group's offices.
The attacks come as rival protests – both for and against President Mohamed Morsi, propelled to power last year by the Muslim Brotherhood – take place in governorates throughout Egypt.
On Saturday, the Islamist group's office in Morsi's hometown of Zagazig in the Nile Delta was also attacked, leaving one dead and 26 injured.
Street battles between the rival camps have also erupted in a number of northern governorates. In Mansoura, one person was killed and over 200 wounded.
Fifty-three people have also been injured in Sharqiya and two in Gharbiya in similar confrontations.
On Friday evening, there were reports that the Freedom and Justice Party’s headquarters in Al-Khanka in Qalioubiya governorate were raided by locals, according to state-owned news agency MENA.
According to eyewitnesses, the office was empty at the time of the attack.