U.S. Embassy: American citizen detained in Egypt

An official with the U.S. Embassy in Cairo confirmed to CBS News the detention of an American citizen in Egypt, CBS News' Alex Ortiz reports from Cairo.

The embassy said it is working with Egyptian authorities to gain access to the detainee and will be providing all appropriate consular services. The American's identity has not been revealed.

The American was among 39 people arrested and detained, all accused of setting fire to a tram, the Agence France-Presse news service reports. It happened during a demonstration against the ouster of Islamist President Mohammed Morsi, the AFP reports.

In the upscale district of Heliopolis in Cairo Friday, supporters of the Muslim Brotherhood set tires on fire which spread to a nearby tramway car, according to the state news agency MENA. Ahmed Helmi, an aide to the Interior Minister, told The Associated Press that the protesters were pro-Brotherhood students from Al-Azhar University, Sunni Islam's most prominent center of learning.

Thousands of Brotherhood supporters around Egypt held protests Friday marking the passage of 100 days since the start of a bloody crackdown against them in the wake of Morsi's ouster. The violence left two dead including a 10-year-old boy.

The Interior Ministry, which is in charge of police, said in a statement that pro-Morsi students set fires and hurled stones inside the campus of Al-Azhar University. They threw stones through the campus fence at police outside, who fired tear gas into university, MENA reported.

Egypt's military launches bloody crackdown on protesters

The marches in multiple districts of Cairo and other cities were commemorating the Aug. 14 storming by security forces on two pro-Morsi protest camps in the capital that killed hundreds of Islamists.

In one of Friday's marches, protesters attempted to enter Rabaah al-Adawiya Square, which was the site of the biggest sit-in camp, in an eastern neighborhood of Cairo. Security forces, who had sealed off the square with barbed wire and armored vehicles, drove the protesters off with volleys of tear gas.

The biggest march in Cairo brought out several thousand protests, who tried to block a main road, then clashed with Morsi opponents in exchanges of stone-throwing. Police fired tear gas to disperse the protest.

A 10-year-old boy died when he was hit in the head by birdshot in clashes that broke out between Morsi supporters and opponents in the city of Suez, according to Ahmed el-Ansari, the head of Egypt's emergency services. The boy was among a crowd of local residents who came out to fight with the Brotherhood protesters, a doctor in the Suez emergency unit told the AP, speaking on condition of anonymity because he was not authorized to talk to journalists.

El-Ansari said another 21-year-old was killed when he was shot in the chest during clashes in eastern Cairo. It was unclear whether he was from the protesters or local anti-Morsi residents. At least 14 people were wounded in clashes nationwide.

Islamists have been holding almost daily protests to denounce the military's July 3 removal of Morsi, the country's first freely elected president. Under the weight of the crackdown since Aug. 14, the protests have mainly been reduced to small and localized gatherings, but at times they have swelled to somewhat larger numbers.

The military ousted Morsi after massive protests by millions nationwide who demanded his removal after a year in office, accusing him and his Muslim Brotherhood of trying to monopolize power. Morsi supporters have accused the military of wrecking the country's nascent democracy with the coup. Thousands of members of the Brotherhood have been arrested since the crackdown began.

The Brotherhood on Friday lashed out Friday at U.S. Secretary of State John Kerry, after he said this week that the Islamist group "stole" the 2011 popular uprising that toppled autocrat Hosni Mubarak.

Kerry's comments about the Brotherhood on Wednesday appeared to be an attempt by Washington to ease tensions with Egypt's new military-backed government. After initial U.S. criticism of the coup, many Egyptians have accused the U.S. of siding with the Brotherhood and Morsi.

Kerry said the activists who led 18-day uprising that brought down Mubarak had not been "motivated by religion or ideology." He said hopes for greater freedom and opportunity and an end to corruption was "what drove that revolution. And then it got stolen by the one single-most organized entity in the state, which was the Brotherhood."

In a statement Friday, the Brotherhood said Kerry was "twisting realities and ignoring facts." It said the Brotherhood "rose to parliament and the presidency through elections" and accused the U.S. of "supporting the military coup ... and ignoring the massacres and oppressive measures that the coup government is carrying out in Egypt."

In Washington, State Department spokeswoman Jen Psaki said Friday that Kerry was "conveying the long-standing, broad U.S. position about revolutions in the Middle East and North Africa" in his remarks about the Brotherhood.

"They were driven by young people, that those were the people who sparked it, that it wasn't driven by extremism of any kind, and that that was the onus of what happened in Egypt," Psaki said. "As we know, at the same time, the Muslim Brotherhood is well organized, they were at the time, and that, of course, led them to power."

At least 600 people were killed on Aug. 14 when riot police cleared the two pro-Morsi camps in Cairo's Rabaah el-Adawiya and Nahda squares.

Protesters on Friday raised Morsi's portraits and held up yellow posters with the symbol of a hand raising four fingers. The word "rabaah" means fourth in Arabic, and the gesture has become a symbol of support for Morsi.

In the southern city of Assiut, police fired tear gas to disperse pro-Morsi protesters and arrested 23. Security officials said they were guarding the city's university campus to prevent protesters from entering.

With the start of the school year in September, Egypt's universities have become the main venue for Brotherhood protests, with marches on campuses nearly every day. Many of them have led to clashes with security forces.

The government on Thursday passed a decision allowing security forces to enter campuses without taking permission from the university president and the prosecutors' office, as previously required.