Report: 870 hurt in Egypt protests

Protesters throw stones at riot police during clashes in Tahrir Square in Cairo, Egypt, during the early hours of June 29.NEW: Forty-eight arrested, an Egyptian official saysGroup forms fact-finding committee to determine what led to the violenceThe government says the violence had been "planned"Tahrir Square was the heart of the revolt against then-President Hosni Mubarak

(CNN) -- Eight hundred and seventy people were hurt earlier this week when a planned memorial for people killed in Egypt's revolution turned into an angry demonstration against the country's interim military government, the Egyptian Organization for Human Rights said Thursday.

Clashes began Tuesday afternoon and continued into Wednesday, with intense confrontations between relatives of victims on one side and security forces on the other.

The human rights group said it has formed a fact-finding committee to interview witnesses and the injured and determine what led to the violence.

Another Cairo-based human rights group, the National Council for Human Rights, issued a statement Thursday condemning the security forces' use of violence against protesters.

For its part, the government said the violence appeared to have been "planned and not organized by the martyr families."

Authorities arrested 48 people in the clashes, said Lt. Col. Yaser Atia with Egypt's National Security.

"There is a conspiracy against Egypt and we will fight it," he said.

An investigation is under way, Atia said.

Many Egyptians are angry at the slow pace of change since President Hosni Mubarak resigned on February 11 after protests.

A group called the January 25 Coalition issued a range of demands Wednesday night, a day after the demonstrations began.

They called for the "speedy trial of snipers and killers of protesters, the removal of Cairo's head of security and the official spokesman of the Ministry of Interior" and "an immediate investigation in the events of last night."

The group, named for the day anti-government protests began this year, also called for the release of detainees held overnight and the "immediate expulsion of security officers who continue to butcher and kill Egyptian people," among other demands.

Protesters burned tires and threw Molotov cocktails, and police responded with tear gas, bullets and pellets in the biggest demonstrations in Cairo in months.

But despite the efforts of police, demonstrators maintained their positions in Cairo's Tahrir Square, increasing their numbers to about 2,000.

Several thousand protesters chanted against Gen. Mohamed Hussein Tantawi, who heads the Supreme Council of the Egyptian Armed Forces. The council has been running the country since Mubarak was forced to step down.

The human rights group Amnesty International has estimated at least 840 people were killed and more than 6,000 wounded during the 18-day revolution that began in late January.

The military-led government that took over when Mubarak resigned has been prosecuting several former officials accused of ordering security forces to fire on protesters.

A police officer accused of killing 20 protesters during a January 28 demonstration has been sentenced to death.

Former Interior Minister Habib El Adly has been sentenced to 12 years for corruption charges but still awaits the verdict for the charge of killing protesters.

Mubarak is scheduled to face the Cairo Criminal Court on August 3 on charges of corruption and deaths of protesters, the Justice Department said Wednesday.

Egypt's military rulers have set parliamentary elections for September.

Journalist Hamdi Alkhshali contributed to this report.

CNN