Parliamentarian Mohamed Abu Hamed was assaulted by unknown attackers on Friday in the Cairo district of Abbasiya.
Abu Hamed had been marching towards Egypt's defence's ministry when he was subject to verbal abuse by several unknown individuals, one of whom reportedly carried a penknife. Abu Hamed's attackers shouted insults at him, describing the MP as a "servant of [business tycoon] Naguib Sawiris."
He was protected, however, by several of the protesters accompanying him who quickly hustled him into a taxi that sped off.
The marches, which converged in Cairo's Abbasiya district, demanded the immediate handover of power from Egypt's ruling Supreme Council of the Armed Forces (SCAF) to a civilian authority.
Abbasiya has witnessed several pro-SCAF rallies in recent months.
Abu Hamed, vice-president of the liberal Free Egyptians party, founded by Sawiris, made headlines following Monday's session of the People's Assembly, the lower house of Egypt's parliament.
During the session, he held a shotgun cartridge aloft as proof that police had used birdshot during recent clashes with protesters near the interior ministry. Abu Hamed made the gesture after parliamentary speaker Saad El-Katatni stated that police had not used birdshot in their confrontation with demonstrators.
In Cairo's Hadayek El-Qubba district, meanwhile, near Abbasiya, pro-SCAF supporters reportedly beat up a handful of protesters marching towards the defence ministry.