Update 8:30 a.m.: Suicide bomber affiliated with the Islamic State, said Turkish officials
A suicide bomber affiliated with the Islamic State group detonated a bomb in a historic district of Istanbul popular with tourists Tuesday morning, killing at least 10 people — nine of them German tourists — and wounding 15 others, Turkish officials said.
Turkish Prime Minister Ahmet Davutoglu said the bomber who carried out the attack in Istanbul's Sultanahmet district was a member of IS and pledged to battle the militant group until it no longer "remains a threat" to Turkey or the world.
Davutoglu described the attacker as a "foreign national." Deputy Prime Minister Numan Kurtulmus had previously said the perpetrator was born in 1988 and was a Syrian national, but the private Dogan news agency claimed the bomber was Saudi-born.
"Turkey won't backtrack in its struggle against Daesh by even one step," Davutoglu said, referring to IS by its Arabic acronym. "This terror organization, the assailants and all of their connections will be found and they will receive the punishments they deserve."
Turkey's state-run news agency said Davutoglu held a telephone conversation with German chancellor Angela Merkel to express his condolences. A senior government official confirmed that most of the victims were German. Merkel had earlier said they were part of a German travel group.
"I strongly condemn the terror incident that occurred in Istanbul, at the Sultanahmet Square, and which has been assessed as being an attack by a Syria-rooted suicide bomber," President Recep Tayyip Erdogan said.
Davutoglu said the death toll of 10 did not include the suicide bomber.
Merkel, speaking at a news conference in Berlin, decried the attack.
"Today Istanbul was hit; Paris has been hit, Tunisia has been hit, Ankara has been hit before," she said. "International terrorism is once again showing its cruel and inhuman face today."
The explosion, which could be heard from several neighborhoods, was at a park that is home to a landmark obelisk, some 25 meters (yards) from the historic Blue Mosque.
Turkey's Dogan news agency reported that one Norwegian and one Peruvian were also among the wounded, and Seoul's Foreign Ministry told reporters via text message that a South Korean had a finger injury. The Norwegian Foreign Ministry told news agency NTB that the Norwegian tourist was slightly hurt and was being treated in a local hospital.
Kurtulmus, the deputy premier, said two of the wounded were in serious condition.
Germany and Denmark have warned their citizens to avoid crowds outside tourist attractions in Istanbul.
Last year, Turkey agreed to take a more active role in the U.S.-led battle against the IS group. Turkey opened its bases to U.S. aircraft to launch air raids on the extremist group in Syria and has carried out a limited number of strikes on the group itself.
It has also moved to tighten security along its 900-kilometer (560-mile) border with Syria in a bid to stem the flow of militants.
The attack comes at a time of heightened violence between Turkey's security forces and militants linked to the outlawed Kurdistan Workers' Party, or PKK, in the country's mostly-Kurdish southeast.
The country is also dealing with more than 2 million Syrian refugees and a wave of migrants from Syria and other countries pouring across Turkey to Europe.
Police sealed the area, barring people from approaching in case of a second explosion, and a police helicopter hovered overhead.
The Sultanahmet neighborhood is Istanbul's main sightseeing area and includes the Topkapi Palace and the former Byzantine church of Haghia Sophia, now a museum.
Erdem Koroglu, who was working at a nearby office, told NTV television he saw several people on the ground following the blast.
"It was difficult to say who was alive or dead," Koroglu said. "Buildings rattled from the force of the explosion."
Halil Ibrahim Peltek, a shopkeeper near the area of the blast told The Associated Press it had "an earthquake effect."
"There was panic because the explosion was violent," he said.
Davutoglu immediately convened a security meeting with the country's interior minister and other officials.
As with previous attacks, authorities imposed a news blackout, barring media from showing images of the dead or injured or reporting any details of the investigation.
Turkey suffered two major bombing attacks last year, both blamed on the Islamic State group.
More than 30 people were killed in a suicide attack in the town of Suruc, near Turkey's border with Syria, in July.
Two suicide bombs exploded in October outside Ankara's main train station as people gathered for a peace rally, killing more than 100 in Turkey's deadliest-ever attack. The prosecutor's office said that attack was carried out by a local IS cell.
Last month, Turkish authorities arrested two suspected IS militants they said were planning suicide bombings during New Year's celebrations in the capital Ankara.
Fraser reported from Ankara, Turkey. Mehmet Guzel in Istanbul, Kirsten Grieshaber and Geir Moulson in Berlin and Jan M. Olsen in Copenhagen, Denmark contributed.
—Lefteris Pitarkis and Suzan Fraser, AP
6:52 a.m.: Explosion in Istanbul kills 10
At least 10 people are dead and more than a dozen wounded, after an explosion struck a historic district in Istanbul Tuesday morning. Civilians and tourists are among the victims from the blast in Sultanahmet Square, site of the famed Blue Mosque.
After the blast, speculation immediately began over who might be responsible, with the target – a historic cultural area that's popular with tourists – leading many to suspect ISIS was behind the attack.
Most of the people killed are foreigners, says Deputy Prime Minister Numan Kurtulmus, who also said police had identified the bomber as a 28-year-old Syrian national.
Turkey's President Reccep Tayyip Erdogan says police believe the explosion, which reportedly struck near where the 3,500-year-old Egyptian Obelisk of Theodosius stands, was the work of a suicide bomber with ties to Syria. Erdogan delivered a lengthy televised address in the wake of the attack.
NPR's Peter Kenyon, who's based in Istanbul, says the blast was strong enough that he heard it from 3 miles away. Peter spoke to British photojournalist Johnny Green, who happened to be visiting the square at the time of the blast. Here's how Green described the scene:
"We'd come out of the Blue Mosque and were just walking onto this boulevard. We were just in the corner, just out of sight. So we heard it, rather than saw. Then, people were just running in every direction. Some people were running towards the action, to help. And other people were just fleeing.... We were very much caught between a rock and a hard place."
Tourists frequently visit the area of the blast, drawn by the green open space and a cluster of historic sites such as the Hagia Sophia and elements of the Hippodrome of Constantinople.
Reporting on the nationality of some of the victims, Hurriyet Daily News reports, "Six German citizens, one Norwegian and one Peruvian were among the ... wounded people rushed to the Haseki Hospital, Doğan News Agency has reported."
The news outlet adds that in the mayhem that followed the attack, a police vehicle crashed and flipped on its side, its siren still blaring; as video from the scene shows, a crowd of onlookers gathered to flip the vehicle back upright.
Tuesday's attack is the latest in a string of terrorist activity in Turkey. In October, some 100 people were killed in a double bombing in Ankara. In December, a blast at an Istanbul airport killed one person. And police said they foiled another double bombing in Ankara that was timed to strike on New Year's Eve.
"Basically, folks here in Istanbul have been on edge for weeks," Peter says, "wondering if something was going to blow up here."
—Bill Chappell, NPR
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