ISTANBUL, Turkey (AFP) – A Syrian suicide bomber yesterday struck the heart of Istanbul’s busiest tourist district, killing 10 people, nine of them Germans, in the latest deadly attack blamed on Islamic State jihadists.

Grisly images from the scene showed several mutilated corpses lying on the ground close to the iconic Ottoman-era Blue Mosque in Sultanahmet, a district which is home to Istanbul’s biggest concentration of historic monuments.

Turkish President Recep Tayyip Erdogan said the attack was carried out “by a suicide bomber of Syrian origin,” while Prime Minister Ahmet Davutoglu said he belonged to the Islamic State extremist group.

“We have determined that the perpetrator of the attack is a foreigner who is a member of Daesh,” Davutoglu said, using an Arabic acronym for IS. Officials earlier said the bomber was a Syrian national born in 1988.

Speaking to AFP, a Turkish official said at least nine of the dead were German, with Davutoglu telephoning Chancellor Angela Merkel to offer his condolences, state media said.

Merkel said the latest attack would deepen German resolve to combat international terrorism.

“Today it hit Istanbul, it has hit Paris, it hit Tunisia, it had already hit Ankara,” she told a news conference in Berlin.

Shortly after the blast, Germany warned its nationals to avoid tourist sites in Istanbul, a city of 14 million that has been hit several times by deadly attacks.

Turkey’s Dogan news agency said nine Germans and two Peruvians were among the wounded.

The explosion took place by the Obelisk of Theodosius, a monument from ancient Egypt which was re-erected by the Roman Emperor Theodosius and stands just outside the Blue Mosque.

Police and ambulances raced to the scene, throwing up a tight security cordon around the area as helicopters hovered overhead, and crowds of worried locals and tourists clamoured to find out what had happened, an AFP correspondent said.

Turkey has been on high alert after a series of attacks blamed on the Islamic State jihadist group including a double suicide bombing in October in Ankara that killed 103 people.

So far there has been no claim of responsibility for yesterday’s attack, but if IS did confirm its involvement, it would raise new fears that the almost five-year conflict in Syria is spilling over Turkey’s borders.