ISIS-affiliated suicide bomber kills 10, injures 15 in Istanbul tourist district

A suicide bomber affiliated with Islamic State in Iraq and Syria (ISIS)detonated a bomb in a historic district of Istanbul popular with tourists Tuesday morning, killing 10 people at least eight of them German tourists and wounding 15 others, Turkish officials said.

Turkish Prime MinisterAhmetDavutoglusaid the bomber who carried out the attack in Istanbul'sSultanahmetdistrict was a member of Islamic State in Iraq and Syria and pledged to battle the militant group until it no longer "remains a threat" to Turkey or the world.

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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 born in Saudi Arabia.

"Turkey won't backtrack in its struggle against Daesh by even one step," Davutoglu said, referring to ISISby its Arabic acronym. "This terror organization, the assailants and all of their connections will be found and they will receive the punishments they deserve."

Germany's foreign minister saideight Germans were among the dead and nine others wounded, some seriously.A Turkish official had earlier said that nine Germans had died. The reason for the discrepancy was not immediately clear.

Turkey's state-run news agency said Davutoglu held a telephone conversation with German Chancellor Angela Merkel to express his condolences.

"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."

Warning to avoid crowds

The explosion, which could be heard from several neighbourhoods, was at a park that is home to a landmark obelisk, some 25 metresfrom the historic Blue Mosque.

The 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 Norway's 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 ISIS. 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-kilometreborder with Syria in a bid to stem the flow of militants.

U.S. State Department spokesman John Kirby condemned Tuesday's attack and pledged to work with Turkey to combat ISIS.

"The United States reaffirms our strong commitment to work with Turkey, a NATO ally and valued member" of the coalition fighting ISIS "to combat the shared threat of terrorism," Kirby said in a statement.

Police seal the area

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 two 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 neighbourhood 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."

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.