They said most of the injuries occurred when civilians believed to be thugs hurled barrages of stones and at least six firebombs at demonstrators, who fought back with stones torn up from the pavements.

Military police, armed with Tasers and batons, fired in the air to stop the demonstrators from approaching the Defense Ministry. A Reuters witness said tear gas fumes were wafting outside the area as military helicopters circled overhead.

An aide to the health minister told state television that 55 people were hurt in the violence, including six who required hospital treatment.

The clashes broke out after the head of the ruling military council, Field Marshal Mohamed Hussein Tantawi, promised in a televised speech to push ahead with elections to transform the Arab world’s most populous nation into a democracy.

Young protesters were angered by clashes between military police and protesters in a number of cities on Friday, in which up to 10 protesters and four policemen were hurt.

The army denied using force against the demonstrators. 

Thousands of protesters marched from Tahrir Square, the epicenter of the Jan. 25 protests that ousted President Hosni Mubarak, toward the Defense Ministry proclaiming their march to be “peaceful, peaceful.”

“The people want to bring down the Field Marshal,” they chanted as they headed for the ministry, snarling traffic.

Tantawi, whose military council took over after Mubarak’s overthrow in February, was seen leaving the compound before the protesters arrived.

A Reuters witness said more than 15 rounds of gunfire, believed to be blanks, were fired into the air. “They are firing at us, they are firing at their own people,” said one of the demonstrators fleeing the area.

It was the 15th day of demonstrations, in Tahrir Square and other squares across the country, to back demands for more freedom for the civilian government, led by Essam Sharaf, an end to military trials and a timetable the completion of reforms.

Sharaf reshuffled his cabinet last week and promised to speed up trials and political reforms.

In his speech to mark the anniversary of the 1952 revolution which overthrew King Farouk in a bloodless coup, Tantawi said his mandate was to deliver an elected government to Egypt.

“We are committed to pressing ahead in turning Egypt to a modern civilian state,” he said.

“We are moving forward on the path to entrenching democracy that upholds freedoms and the rights of citizens through free and fair elections,” he added in a pre-recorded speech, his first address to the public since Mubarak was ousted.

Tantawi, Mubarak’s defense minister for two decades, did not give details, but spoke broadly of a “united front” to confront challenges facing Egypt both domestically and abroad.

“The decisive period in our people’s history requires concerted efforts from all Egyptians to confront the urgent challenges facing us that cannot be dealt with by hesitation or semi-solutions,” Tantawi said, citing efforts to limit the economic damage caused by the uprising.

Many ordinary Egyptians fear continued protests are derailing efforts to kick-start an economy that was hard hit when investors and tourists fled.

The ruling military council, in a statement on its Facebook page, denied the authorities used force against demonstrators and accused the April 6 Movement, one of the main groups behind the uprising that toppled Mubarak, of trying to drive a wedge between the armed forces and the people.

April 6 described the statement as “misleading allegations.”

“We will be the last to leave Tahrir Square, either alive with our heads held high after triumphantly achieving the demands of the Egyptian people or as martyrs for the sake of God and the nation,” the group added.