Several people reportedly dead after an explosion in popular Istanbul tourist spot.

Up to 10 people are feared dead and 15 others seriously injured after an explosion rocked a square popular with tourists in Turkey’s most populated city.

Turkey’s Haberturk TV said at least eight people were killed in the blast in Istanbul’s Sultanahmet Square, close to popular tourist attractions the Blue Mosque and Hagia Sophia.

The Telegraph reports the attack was believed to have been carried out by a female suicide bomber.

Security expert Michael Horowitz said it was an “attack on tourists”, with initial reports suggesting the victims are French and German.

Turkish police have sealed off part of the square and emergency services are at the scene.

It is the latest in a series of fatal attacks across the country in recent months.

In early October, 103 people were killed when two suicide bombers attacked a crowd in the capital, Ankara.

The country is on high alert after the horrible attack was blamed on Islamic State jihadists.

Several suspected IS members were arrested in recent weeks with authorities claiming they were planning attacks in Istanbul.

*Image via Twitter/@Cihan_Dishaber.