An explosion in a historic district of Istanbul popular with tourists killed 10 people and injured 15 others Tuesday morning, the Istanbul governor's office said.<br />The cause of the explosion in the Sultanahmet district was being investigated, but state-run TRT television reported it was likely caused by a suicide bomber.<br />Private NTV television said the explosion, which could be heard from several neighborhoods, was close to a park that is home to a landmark obelisk.<br />Police sealed the area, barring people from approaching in case of a second explosion.<br />The Sultanahmet neighborhood is Istanbul's main sightseeing area and includes the Topkapi Palace and Blue Mosque.<br />Turkey suffered two major bombing attacks last year, both blamed on the Islamic State group.
