The blast on Istiklal Avenue left 81 people hurt.

The prime suspect, identified as 23-year-old Syrian national Ahlam Albashir, said she had taken orders from the PKK/YPG terrorist organisation's headquarters in Ayn al Arab in northern Syria, the Istanbul General Security Directorate said in a statement on Monday as quoted by TRT World.

A total of 46 suspects were detained after police carried out operations at 21 addresses after inspecting footage from 1,200 security cameras, police said in a statement released on Twitter.

"If we had not caught the perpetrators [of the bomb attack in Istanbul], they would have fled to Greece today," Turkish Interior Minister Suleyman Soylu said in a separate statement.

Based on initial information from Istanbul Governor Ali Yerlikaya, President Recep Tayyip Erdogan said the explosion could be an act of terrorism, reports TRT World.

"It would be wrong to say this is undoubtedly a terrorist attack, but the initial developments and initial intelligence from my governor is that it smells like terrorism," Erdogan said.