A news conference organised by civil aviation employees on Saturday with the intention of disclosing documents they say prove Ahmed Shafiq's corrupt dealings was cancelled after supporters of the former Egyptian civil aviation minister broke into the hall and started a brawl.

The conference on the fourth floor of the Journalists' Syndicate in downtown Cairo was interrupted at the very beginning by dozens of Shafiq's supporters – some of them thuggish-looking - cursing the civil aviation employees and chanting Shafiq's name.

The employees replied with aggressive counter chants and as tensions escalated, the verbal exchanged developed into a fistfight between both sides.

An Ahram Online reporter was deliberately punched in the face by one of Shafiq's supporters as a group of intruders were physically assaulting one of the civil aviation employees. The reporter suffered no injuries.

Ahram Online contacted the official campaign team, but has yet to receive confirmation whether members of their team were at the civil aviation employees' press conference.

Amid the chaos someone, presumably an organiser, announced through the sound system that the conference was cancelled and asked everyone to evacuate the hall.

As people were leaving, the violence tailed off outside the conference hall, but both sides - dozens of men and women each - kept chanting against each other.

Amid the employees' hysterical chants was the standard "Down, down with the military rule," which has been repeated in many protests organised by revolutionary forces. They also vociferously chanted many slogans against Shafiq, which was Mubarak's last prime minister. "Tahrir says Shafiq is one of the remnants [of the former regime]," and "Shafiq is a thief."

More emotional supporters set pictures of Shafiq aflame; others threw his posters on the ground and repeatedly stomped on them. The Shafiq supporters, on the other hand, rose aloft pictures of the military Colonel General and chanted his name.

After Shafiq supporters left the Journalists' Syndicate fourth floor, some of the civil employees took the opportunity to speak with the journalists who were there to cover the conference. Some of them insisted on flashing their identification cards to cameras and reporters, while others distributed some of the documents they had with them to "prove the corruption Shafiq is involved in."

One of the protesters was engineer Abdel Hamid Amer, who told Ahram Online that he had pressed 11 charges against Shafiq. "I am a contractor who worked with the [Cairo] Airport, and I am aware of the corruption going on," he said.

The gates of the Journalists' Syndicate were closed for a short while and were opened after the turmoil cooled down.

Shafiq campaigners, who announced his intention to run for president in December 2011, have boasted "unprecedented developments he achieved during his tenure as a civil aviation minister."