Minutes past 10pm, Mohamed El-Badry, a member of the General Secretariat of the Revolution, told Nile TV , which is carrying live footage from the square, that scores of what appeared to be armed men were launching an attack on the square from the direction of Abdel Moneim Riad.
"I can see molotov thrown into the square and I hear gun shots fired," El-Badry said. "There are also people standing on top of 6 October bridge which overlooks the square, and they are throwing stones at protesters," El-Badry said.
"Two people have been shot in the eye and ambulances have transferred them to one of the field hospitals in the square at Omar Makram mosque for emergency treatment," El-Badry added.
Nile TV footage did show a few hundred people who appeared to be protesters rushing towards Abdel Moneim Riad to confront the attackers.
Mohamed El-Sa'id, a member of the Revolution Youth Coalition, told state Nile TV that hundreds of people are exchanging molotov cocktail bombs in Abdel Moneim Riad square, but he asserted that protesters sitting-in in Tahrir square against the ruling military council (SCAF) are not involved.
Earlier Tuesday evening, activists in Tahrir Square told Ahram Online that several men wearing red T-shirts and wielding truncheons have attacked a number of street vendors who sell food and tea to the thousands of protesters who have been holding a sit-in at the Square since November 19.
"The men in red tried to wreak havoc in the square, and they claimed to be part of a 'Tahrir public safety brigade', " Ahmed Kamal, an activist who is currently in the area told Ahram Online.
Kamal, who is still in the centre of the massive square a few hundred yards from Abdel Monein Riad, confirmed to Ahram Online at 10:30pm that he heard gun shots coming from the direction of Riad.
"I have not seen any army or police in the area so far to attempt to separate the two sides," El-Badry, on the other hand, told Nile TV.
Ahram Online reporters have confirmed that individuals in civilian clothes, not soldiers in uniform, are the ones attempting to attack the square.
Ahram Online reporters also spotted an army tank moving up El-Galaa street in the direction of Abdel Moneim Riad.
The number of protesters in the Square has thinned out in the last 24 hours as millions of Egyptians flocked to polling stations to cast ballots in the parliamentary elections.