A supporter of Egypt's ousted President Mohammed Morsi watches for a generator outside Rabaah al-Adawiya mosque, where protesters have installed a camp and held daily rallies at Nasr City, Cairo, Egypt, Tuesday, Aug. 13, 2013.

CAIRO - Egyptian security forces, backed by armored cars and bulldozers, moved on Wednesday to clear two sit-in camps by supporters of the country's ousted President Mohammed Morsi, showering protesters with tear gas as the sound of gunfire rang out at both sites, state television and security officials said.

At least two members of the security forces were confirmed to have died in the morning's crackdown while a group representing the protesters said as many as 25 protesters were killed in one of the camps.

The smaller of the two camps was cleared of protesters by late morning, with most of them taking refuge in the nearby Orman botanical gardens and inside the sprawling campus of Cairo University.

However, security forces remained on the fringes of the other camp in the eastern Nasr City district after it showered the encampment with tear gas. Television footage from there showed thousands of protesters congregating at the heart of the site, with many wearing gas masks or covering their faces to fend off the tear gas.

A security official said a total of 200 protesters have been arrested from both sites. The official spoke on condition of anonymity because he was not authorized to speak to the media.

The Anti-Coup Alliance, an umbrella of pro-Morsi supporters, said in a statement that 25 were killed and dozens injured in the attack on the Nasr City camp, claiming that security forces used live ammunition. The Interior Ministry, which is in charge of the police, said it only used tear gas and that its forces came under fire from the camp. Two policemen were killed and five were injured by gunfire, it said.

A ministry statement also warned that forces would deal firmly with protesters acting "irresponsibly," suggesting that it would respond in kind if its men are fired upon. It said it would guarantee safe passage to those who want to leave the Nasr City site but would arrest those wanted for questioning by prosecutors.

An Associated Press television video journalist at the scene in Nasr City said he could hear the screams of women as a cloud of white smoke hung over the protest encampment. He said a bulldozer was removing mounds of sand bags and brick walls built earlier by the protesters as a defense line in their camp.

Army troops did not take part in the two operations, but provided security in the areas. Police and army helicopters hovered over both sites as plumes of smoke rose over the city skyline. The simultaneous actions by the Egyptian forces began shortly after 7 a.m. (0500 GMT).

Regional television networks were showing images of collapsed tents and burning tires at both sites, with ambulances on standby. They were also showing protesters being arrested and led away by black-clad policemen.

At one point, state television showed footage of some dozen protesters, mostly bearded, cuffed and sitting on a sidewalk under guard outside the Cairo University campus.

At least 250 people have died in clashes in Egypt following Morsi's ouster in a military coup that followed days of mass protests by millions of Egyptians calling for his removal.

Supporters of the Islamist president want him reinstated.

"The world cannot sit back and watch while innocent men, women and children are being indiscriminately slaughtered. The world must stand up to the military junta's crime before it is too late," said a statement by the Muslim Brotherhood, the Islamist group from which Morsi hails.