A number of Egyptians were reported killed Thursday at Tahrir Square in Cairo, the scene of Wednesday's battles between forces backing President Hosni Mubarak and the protesters occupying the square in a bid to force him to resign.

Reuters news agency reported that five had died and that pro-Mubarak forces were responsible for the killings, having opened fire on protesters. Agence France-Presse quoted a doctor on the scene as saying four had died, taking the death toll to seven over a 24-hour period.

Earlier, a human rights monitor reporting from Tahrir Square reported that gunfire had intensified in the early hours of Thursday.

"We are now hearing regular bursts of automatic fire every few minutes, as well as some heavier rounds from the mounted guns on the army's armored cars," said Human Right Watch's Peter Bouckaert. "It is now just after 5, and for the last 10 minutes shots have rang out almost continuously."

Agence France-Presse reported that Dr. Amr Bahaa, a doctor operating from a makeshift hospital at a mosque near the square, estimated that more than 1,000 people had been wounded since Wednesday.

"Most of the casualties came in in the last three hours, many with gunshot wounds," AFP quoted him as saying. The agency reported witnesses as saying many had been injured by gunfire coming from a bridge occupied by Mubarak supporters.

Later Thursday morning, Reuters said anti-Mubarak protesters had barricaded themselves into the square, and that Egyptian soldiers had opened up a buffer zone to keep the two sides apart.

Report updated at 1.30pm Cairo time