Egyptian police said on Monday they have arrested three suspects over the bombing of a famed Cairo bazaar that killed a French teenager and wounded 25 people, most of them tourists, AFP reported.
Sunday's attack was the first deadly violence against Westerners in Egypt since 2006 but as yet there has been no claim of responsibility.
The bomb blast ripped through a street lined with cafes and restaurants in Khan al-Khalili, a 1,500-year-old market that is one of the Egyptian capital's main tourist attractions.
"Three people there were arrested on the site as suspects after the attack," a police official said on Monday. "Others are being questioned as witnesses."
The 17-year-old French girl, who died in hospital from her injuries, was part of a tour group of 54 teenagers from the Paris region who had hoped to buy souvenirs before heading home on Monday.
The bomb wounded 17 of her fellow tourists, including one seriously, French and Egyptian officials said.
"There was a very powerful explosion. Then screams and blood. We all started running," said Romy Janiw, 28, one of the seven adults accompanying the teenagers.
Egyptian deputy health minister Nasir Rasmi told AFP the other wounded included a 37-year-old German, three Saudis and four Egyptians.
"Most of the injuries were small shrapnel wounds," he said.
Mohammed Ismail, who worked in a nearby cafe and was lightly wounded in the attack, said he was watching a football game in a cafe and had stepped out onto the street before the bomb exploded.
"I didn't see the bomb," he told AFP after leaving hospital. "The force of the blast threw me. All I could see was grey smoke. Then I fell unconscious."
A pool of congealing blood was visible on the marble entrance to the Hussein mosque, which is one of Egypt's oldest places of worship.
Witnesses said the force of the explosion shook surrounding buildings. "The building shook and the books fell of the shelf," said a woman who worked in a store that sold Korans.
Medics wheeled the tourists who were released onto a bus parked outside the emergency room, waiting to take them to the Cairo airport. A girl quietly sobbed as a friend tried to comfort her. They were due to board a flight to Paris on Monday morning.
There were conflicting accounts as to how the attack was carried out.
Witnesses and a police official told AFP that two rudimentary bombs were thrown from a rooftop overlooking the street. The second device failed to detonate and was blown up in a controlled explosion, a police source said.
A Western diplomat who accompanied the wounded to hospital said they told police investigators that the bombs had been hurled at them from a rooftop.
But Amin Rady, a member of the Egyptian parliament national security committee, told AFP that police suspected that a "primitive" bomb had been placed under a concrete bench, which was shattered by the explosion.
The bombs went off outside the Al-Hussein hotel, just across the square from the Hussein mosque.
The head of Cairo's Al-Azhar University -- Sunni Islam's highest religious authority -- condemned the bombing.
"Those who carried out this criminal act are traitors to their own religion and their nation, and they are distorting the image of Islam which rejects terrorism and bans the killing of innocents," Sheikh Mohammed Sayyed al-Tantawi said.
It was the first deadly attack on tourists in Cairo since a bombing in the same neighbourhood killed two tourists and wounded 18 in 2005.
A series of bombings killed scores of people in Red Sea resorts on the Sinai peninsula from 2004 to 2006 that were blamed on militants loyal to Al-Qaeda.
Egypt was struck by a spate of deadly attack on tourists by Islamic militant groups in the 1990s that dealt a savage blow to the vital tourism sector.
Last year, a total of 13 million tourists visited Egypt, earning it 11 billion dollars in revenue. The industry also employs 12.6 percent of the workforce.