ISTANBUL: A suicide bomber killed at least 10 people, most of them German tourists, in Istanbul`s historic district on Tuesday, in an attack Prime Minister Ahmet Davutoglu blamed on the militant Islamic State (IS) group.

All of those 1(illed in Sultanahmet square, near the Blue Mosque and Hagia Sophia major tourist sites in the centre of one of the world`s most visited cities were foreigners, Mr Davutoglu said.

A senior Turkish official said nine were German, while Peru`s foreign ministry said a Peruvian man also died.

Deputy Prime Minister Numan Kurtulmus said the bomber was believed to have recently entered Turkey from Syria but was not on Turkey`s watch list of suspected militants.

He said earlier that the bomber had been identified from body parts at the scene and was thought to be a Syrian born in 1988.

Mr Davutoglu said he had spoken by phone to German Chancellor Angela Merkel to offer condolences and vowed Turkey`s fight against IS, at home and as part of a US-led coalition, would continue.`Until we wipe out Daesh, Turkey will continue its fight at home and with coalition forces,` he said in comments broadcast live on television, using an Arabic name for IS.

He vowed to hunt down and punish those linked to the bomber.

Several bodies lay on the ground in the square, also known as the Hippodrome of Constantinople, in the immediate af termath of the blast.

It was not densely packed at the time of the explosion, according to a police officer working there, but small groups of tourists had been wandering around.

`This incident has once again shown that as a nation we should act as one heart, one body in the nght against terror. Turkey`s determined and principled stance in the fight against terrorism will continue to the end,` President Tayyip Erdogan told a lunch for Turkish ambassadors in Ankara.

Norway`s foreign ministry said one Norwegian man was injured and was being treated in hospital.

Turkey, a Nato member and candidate for accession to the European Union, is part of the US-led coalition against IS fighters who have seized territory in neighbouring Syria and Iraq, some of it directly abutting Turkey.

There was no immediate claim of responsibility but Islamist, le ftist and Kurdish militants, who are battling Ankara in southeast Turkey, have all carried out attacks in the past.`We heard a loud sound and I looked at the sky to see if it was raining because I thought it was thunder but the sky was clear,` said Kuwaiti tourist Farah Zamani, 24, who was shopping at one of the covered bazaars with her father and sister.

The dull thud of the blast was heard in districts of Istanbul several kilometres away, residents said.

Television footage showed a police car which appeared to have been overturned by the force of the blast.

Tourist sites including the Hagia Sophia and nearby Basilica Cistern were closed on the governor`s orders, officials said.

`At first we thought it was percussion bomb, it was so loud. They attacked Sultanahmet to grab attention because this is what the world thinks of when it thinks of Turkey, said Kursat Yilmaz, who has operated tours for 25 years from an office near the square.

`We`re not surprised this happened here, this has always been a possible target,` he said.

Ambulances ferried away the wounded as police cordoned off streets. The sound of the call to prayer rang out from the Blue Mosque as forensic police officers worl(ed at the scene.

`It was unimaginable,` the police officer who had been working on the square said, describing an amateur video he had seen of the immediate aftermath, with six or seven bodies lying on the ground and other people seriously wounded.-Reuters