Fighting has erupted in Cairo between groups opposed to Hosni Mubarak and those who support the Egyptian President, the day after Mubarak announced he will not seek re-election.

According to the Al Jazeera news agency, more than 100 people have been injured in clashes at Tahrir Square, the center of anti-Mubarak demonstrations the past few days. Witnesses said thousands of Egyptians allied to Mubarak entered the square and thereafter the fighting began.

Reportedly, soldiers at the scene did not intervene.

Jane Dutton of Al Jazeera was quoted as saying that hundreds of anti-government supporters were running from the square, including many women and children. Another Al Jazeera

Reporters claimed that men riding on horseback and even on camels raced into the crowds, as army officers stood by.

The army had barricades to block them off but they got through them and the army let them through,” one eyewitness told Al-Jazeera.The people on horses are pro-Mubarak supporters; they are a very angry crowd looking for anyone working for Al Jazeera and for Americans. They are trying to get on the other side of the army tanks to get to the anti-Mubarak supporters. More and more pro-Mubarak supporters are coming in and for now the army is acting as a buffer.

Opposition groups claimed that many of the Mubarak supporters in the crowd were either thugs or policemen in plainclothes.

Members of security forces dressed in plain clothes and a number of thugs have stormed Tahrir Square, opposition groups said.

Dutton also noted that a reporter working for the Al-Arabiya channel was stabbed during the clashes.