Thousands of Egyptian riot police beat pro-democracy activists Thursday, chasing and dragging them through the streets to break up a demonstration in support of judges who blew the whistle on election fraud.

The violence appeared to signal a tough new zero tolerance stance by the government toward protests demanding reform and expressing discontent that President Hosni Mubarak has backed off promises of democratic change.

The State Department said it was "deeply concerned" about the police assault on protesters and would raise the matter with the government.

"We urge the Egyptian government to permit peaceful demonstrations on behalf of reform and civil liberties," spokesman Sean McCormack told reporters at the State Department's daily briefing.

The protests were called to support two judges from Egypt's highest court who have become heroes of the democracy movement after they went public with allegations of fraud during parliamentary elections last year.

The judges, Hisham el-Bastiwisy and Mahmoud Mekki, have been ordered before a court panel for possible disciplinary action. But they boycotted their hearing Thursday to protest the treatment of the demonstrators and the session was postponed until May 18.

"This is not a trial, this is a scandal," el-Bastiwisy told The Associated Press. "All those troops are not for our trial, it's because they are afraid of the nation. They are beating people up like mad in the streets."

Hundreds of protesters who turned out for the scheduled hearing were met by a massive security force, with lines of riot police wielding long sticks and cordoning off streets around the court in downtown Cairo.

Uniformed police chased protesters through the streets, grabbing them and beating some before dragging them toward waiting trucks or into nearby buildings.

Dozens were arrested, police officials said, without giving precise numbers.

"This is what the regime is doing to us ... we are victims and strangers in our homeland," one protester, Hafez el-Fergani, shouted before police chased after him.

Police pulled an elderly woman by her arms, trying to drag her into a police van. When she resisted, the policemen tore the front of her robe, throwing her sprawled on the pavement with her underclothes exposed, said a witness, activist Bothaina Kamel. Other witnesses reported police pulling women activists and journalists by the hair.

Nearby, police beat a man with sticks, then kicked him after he fell to the pavement, Kamel told the AP.

In one square, about 50 protesters chanted slogans and held banners in support of the judges when nearly 200 plainclothes policemen swarmed in and chased the activists, punching those they could reach, witnesses said.

Police beat a cameraman for Al-Jazeera television in his face and confiscated his camera and tape, said Lina el-Ghadban, an Al-Jazeera reporter. The police smashed the camera of a Reuters photographer and pushed and shoved a Reuters TV cameraman, then dragged him on the ground and confiscated his camera, Reuters reported.

An AP reporter who was covering the protest was pushed to the ground and stepped on by uniformed police who surged through the crowd to chase protesters.

While most protesters were secular activists, police arrested 120 members of the opposition Muslim Brotherhood during a rally at a mosque in solidarity with the judges, the Brotherhood said on its Web site. The Web site's director, Abdel Gelil el-Sharnoubi, told the AP about 300 Brotherhood members had been detained across the country, including those arrested in Cairo. The police did not confirm those figures.

Police had already arrested 48 pro-reform activists since putting down similar protests during the first session of the judges' hearing April 27.

The tough response comes as the government faces worries on several fronts. Security fears have increased after an April 24 bombing in the Sinai tourist resort of Dahab killed 21 people — the third terror attack on a resort in two years. And the government has faced political pressure from the Muslim Brotherhood.

In early 2005, police allowed pro-democracy demonstrators to carry out an unprecedented campaign of street rallies calling for change.

Soon after, Mubarak allowed the country's first multi-candidate presidential elections. He easily won re-election, but promised further changes in a country he has ruled unchallenged for more than a quarter century.

But parliamentary elections in November and December were marred by violence that killed 14 people, and security forces in many cases barricaded polling sites to prevent opposition supporters from voting.

Still, the Muslim Brotherhood was able to increase its presence in parliament six-fold to 88 seats — making them the country's strongest opposition movement. Since then, the government has put off local elections for two years, apparently for fear of further gains.

Last month, the government renewed emergency laws that it had promised to lift, a longtime demand of human rights groups because the laws give security forces broad powers of arrest.