Update, 4:18 pm: Tourists from German and Norway were among the injured in the explosion at the Istanbul's Sultanahmet square, CNN Turk television reported. 

Germany has warned its citizens in Istanbul to not visit tourist sites in the Turkish city, according to reports.

Update, 3:13 pm: At least 10 people were killed and 15 others injured in the explosion at Sultanahmet square in Turkey's Istanbul, Anadolu Agency cited the governor's office statement. 

Turkish officials suspect terror link in the blast, according to AFP.

Original Story:

At least eight people were killed and several others injured in an explosion at Sultanahmet square in Turkish city of Istanbul on Tuesday, Turkey's Haberturk television reported.

The broadcaster reported that the blast was caused by a suicide bomber, according to Reuters.

The explosion occurred at 10:20 am local time (1:50 pm IST) at the major tourist attraction in Istanbul, according to Anadolu Agency.

Ambulances and police teams were rushed to the blast site. The injured people were shifted to nearby hospitals, including Haseki Training and Research Hospital.

Crime Scene Investigation branch of Istanbul and Bomb Disposal Squad have also reached the spot and are trying to determine the cause of the explosion.

The Turkish police have sealed the blast site and restricted the public and journalists from going near it. 

"We understand there are some injuries, but we don't know if anyone has lost their life yet... Eyewitnesses have said that the blast was heard from other neighbourhoods," Al Jazeera quoted its journalist reporting from Istanbul as saying.

The historic Sultan Ahmed Mosque or the Blue Mosque and Hagia Sophia, a museum, is located in the area.