The Egyptian army has intervened to separate anti-government demonstrators and alleged supporters of President Hosni Mubarak at Cairo's Tahrir Square.

As the massive anti-government protests in Cairo and Egypt's other major cities continue, the country has seen deadly clashes between the civic movement and supporters of President Hosni Mubarak, who are suspected of being paid thugs hired by the regime.

Five men were shot dead in gunfire in downtown Cairo overnight as Mubarak supporters are said to have assailed protesters camping in Tahrir Square.

Around mid day on Thursday, the Egyptian army has fended off an attack attempt on the unarmed anti-government protesters, international media reported.

The new developments in the streets of Cairo came after earlier on Thursday Prime Minister Ahmed Shafiq made an unprecedented apology for the assault by regime backers that turned central Cairo into a battle zone.

The protesters continue to accuse the Mubarak regime of "fashioning" gangs of "supporters" by using hired thugs and policemen in civilian clothes, whose purpose is to harass the anti-government movement.

For the first time on Thursday, the Egyptian army, which has been witnessing the protests in the streets since Friday, has started to engage in combat action against the suspecter provocateurs from the pro-Mubarak camp as it established a security cordon between the two opposing camps.

The groups clashed overnight, leaving five people dead and more than 800 wounded.

The two sides traded volleys of rocks and Molotov cocktails for much of Wednesday night, until automatic gunfire and powerful single shots rained into the square starting at around 4 a.m. and continuing for more than two hours.