An explosion at Istanbul's historic Sultanahmet district, which is popular with tourists, has injured several people on Tuesday, Turkish media reports said.
   
The cause of the explosion was not immediately known.
  
Private NTV television said the explosion was close to a park that is home to a landmark obelisk. The state-run Anadolu Agency says several police and medics were sent to the area.
 
Police sealed the area, barring people from approaching in case of a second explosion.
 
The Sultanahmet neighborhood is Istanbul's main sight-seeing area and includes the Topkapi Palace and Blue Mosque.
 
Turkey suffered two major bombing attacks last year.
 
More than 30 people were killed in an Islamic State suicide attack in the town of Suruc, near Turkey's border with Syria, in July.
 
Two suicide bombs in October outside Ankara's main train station as people gathered for a peace rally killed more than 100 people. It was Turkey's deadliest attack. The prosecutor's office said the attack was carried out by a local Islamic State cell. (AP)