An explosion in the historic square of Sultanahmet in Istanbul left at least 10 people dead and wounded 15 others Tuesday.

"We heard a really big explosion. ... I didn't really understand what was happening," said Ali Hakan Ataman to VOA News. "Blood and flesh were splattered on us and I am sure I saw at least six or seven people laying on the ground dead. I am still in shock."

Officials said they suspect a Syrian suicide bomber detonated the explosion. They said they believe the suicide bomber had ties to the terror group Islamic State, according to Reuters.

The Turkish government has been attacked by Islamist and Kurdish militants in the past months. The Sultanahmet attack took place while government security forces crack down on the Kurdish rebel group, the PKK.

Ataman said he thought German tourists were among the victims.

Another witness, Erdogan Salihli, said the explosion was huge.

"All the buildings around were shaking, and it was very strong and threw people off the ground," he said. Panic and fear ensued.

"All was quiet for a second or a bit longer. I've never seen an explosion in this magnitude. As people were trying to figure out what really happened, the cries of people at the scene was very tragic."