An explosion Istanbul killed 10 people and injured 15 others

A Syrian suicide bomber detonated a bomb in a historic district of Istanbul popular with tourists Tuesday morning, killing at least 10 people and wounding 15 others, Turkish officials said.

President Recep Tayyip Erdogan said in televised remarks that both Turks and foreigners were among the dead in the explosion in the Sultanahmet district.

"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," Erdogan said.

Deputy Prime Minister Numan Kurtulmus said the bomber was a 28-year-old Syrian national whose "connections" were being investigated. He said most of the people who died were foreigners. It was unclear whether the death toll of 10 included the alleged bomber.

At least nine of the wounded were German nationals. German Chancellor Angela Merkel, speaking at a news conference in Berlin, said Germans from a group traveling together could also be among the dead.

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 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.

There was no immediate claim of responsibility for the attack, although theIslamic State group was suspected. Kurdish militants and left-wing groups are active in Turkey.