CAIRO — Groups of men armed with knives and sticks attacked thousands of protesters trying to march to the headquarters of Egypt's military rulers Saturday, setting off fierce street clashes and leaving more than 100 injured, most lightly. Security fired tear gas to disperse the crowd.

The clashes come as tensions mount between the military council that took control of the country after a popular uprising ousted ex-President Hosni Mubarak and activists who want them to move faster in bringing former regime officials to justice and setting a date for the transition to civilian rule.

The military has appeared impatient with the pressure, accusing activists of treason, warning protesters against "harming national interests" and calling on "honorable" Egyptians to confront actions that disrupt a return to normal life.

An estimated 10,000 people set out from downtown Cairo's Tahrir Square but were stopped from reaching the military headquarters in the eastern Abbasiyah neighborhood by a line of army barricades. Along the way, they chanted slogans against the military council's delay in implementing their demands.

The march coincided with the 59th anniversary of the 1952 military coup that toppled the monarchy and brought a series of military leaders to office, ending with Mubarak.

"Down with the ruler of the military," the protesters chanted.

Bands of men armed with knives and sticks set upon them from side roads and from in front of the military barricades, setting off pitched street battles in which both sides threw punches and hurled rocks.

Gunfire was heard, but it was unclear who was shooting. Some firebombs were thrown, igniting large blazes in the middle of the street and near buildings.

The identity of the attackers could not immediately be determined. Similar groups of men have tried to break up other rallies, and Mubarak's regime often used hired thugs to attack protesters. Some witnesses said they might have been residents or shopkeepers angry at the loss of business as a result of the protests. Others said local residents threw water bottles to the protesters and helped them reach safety.

At one point, a man perched over a female protester, squeezing her against the wall where she was taking cover from the flying rocks. The man cursed her and accused her of being hired to cause chaos.

The man shouted: "Damn your revolution!"

An Associated Press reporter saw a firebomb flying from inside a garden lining a side street, landing at a distance from the protesters. The attackers then charged toward the protesters and accused them of throwing the flaming bottle.

"We are extremely angry. These are Egyptians beating us," said protester Selma Abou el-Dahab.

A medical official said more than 140 people were hospitalized with wounds from thrown rocks and falling in the stampede. He spoke on condition of anonymity because he wasn't authorized to speak to the press.

The violence broke out following a televised speech by Field Marshal Mohammed Hussein Tantawi, the head of the ruling military council, who attempted to diffuse the tension by praising the youth who led the uprising that toppled Mubarak. The speech was to commemorate the 1952 coup anniversary.

Many protesters have grown distrustful of the military rulers who assumed control of the country on Feb. 11. A few hundred have been camped out in Tahrir Square since July 8 to pressure the military to bring those accused of killing nearly 900 protesters during the 18-day uprising to trial.

So far, only one low-ranking policeman has been charged in absentia for killing protesters.

Critics accuse the generals of dragging their feet in bringing former regime officials to trial and purging the government of Mubarak loyalists as well as trying civilians in military courts.

But not all activists supported the march toward the military council. Hafez Abou Saada, a prominent human rights activist and longtime democracy advocate, said the rally was a call "for confrontation that no one needs."

Saturday's march was the second consecutive day that protesters tried to reach the headquarters of the Supreme Council of the Armed Forces. On Friday, crowds tried to reach the building to denounce the purported beatings of demonstrators by military forces during another rally in the city of Alexandria.

Tantawi appealed for national unity and called the youth activists "a great product of Egyptian soil."

The military council has promised to hand over power to an elected civilian government within six months. Parliamentary elections are now set for October or November, followed by presidential elections, likely next year.

In a statement released on its Facebook page, the army denied using violence against protesters in Alexandria on Friday and accused activists of seeking to drive a wedge between it and the people.

"The Supreme Council of the Armed Forces urges the public to exercise caution and not to be drawn into this suspicious plot that aims to undermine Egypt's stability," the statement said in unusually strong language.

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It singled out the April 6 movement, one of the largest groups behind the protests that forced Mubarak to step down.

Activists responded by saying the army rejects all criticism of how it is ruling the country.

Mohammed Adel, an April 6 spokesman, said "defaming" the group is reminiscent of the language used by the previous regime against its opponents. "It is the army that is driving a wedge between it and the people by accusing others of treason," he said.

Associated Press writer Ben Hubbard contributed to this report.