Police have arrested a suspect who is believed to have planted the bomb that exploded and killed six people on a bustling pedestrian avenue in Istanbul.

Turkey’s interior minister made the announcement on Monday, adding that initial findings indicate Kurdish militants were responsible for the deadly attack.

Several dozen people were also were wounded in Sunday’s explosion on Istiklal Avenue, a popular thoroughfare lined with shops and restaurants that leads to the famous Taksim Square.

People leave the area after an explosion
People leave the area after an explosion on Istanbul’s popular pedestrian Istiklal Avenue (Can Ozer/AP)

“A little while ago, the person who left the bomb was detained by our Istanbul Police Department teams,” the Anadolu Agency quoted Interior Minister Suleyman Soylu as saying. 

He did not identify the suspect but said 21 other people were also detained for questioning.

Sunday’s explosion was a shocking reminder of the anxiety and safety concerns that stalked the Turkish population during years when such attacks were common.

The country was hit by a string of deadly bombings between 2015 and 2017, some by the so-called Islamic State group, others by Kurdish militants who seek increased autonomy or independence.

The minister said evidence obtained pointed to the Kurdistan Workers’ Party, or PKK, and to its Syrian extension, the Democratic Union Party, or PYD.

He said the attack would be avenged.

“We know what message those who carried out this action want to give us. We got this message,” Mr Soylu said.

“Don’t worry, we will pay them back heavily in return.”

Mr Soylu also blamed the United States, saying a condolence message from the White House was akin to a “killer being first to show up at a crime scene”.

Turkey has been infuriated by US support to Syrian Kurdish groups.

Security and ambulances at the scene after an explosion on Istanbul’s popular pedestrian Istiklal Avenue
Security and ambulances at the scene after an explosion on Istanbul’s popular pedestrian Istiklal Avenue (Emrah Gurel/AP)

He said security forces believe that instructions for the attack came from Kobani, the majority Kurdish city in northern Syria that borders Turkey.

In its condolence message, the White House said it strongly condemned the “act of violence” in Istanbul, adding: “We stand shoulder-to-shoulder with our Nato ally (Turkey) in countering terrorism.”

Mr Soylu said of the 81 people who were hospitalised, 50 were discharged. Five of the wounded were receiving emergency care and two of them were in life-threatening condition, he said.

The six who were killed in the blast were members of three families and included a 15-year-old and a nine-year-old.

Istiklal Avenue was reopened to pedestrian traffic at 6 am on Monday after police concluded inspections at the scene. People began leaving carnations at the site of the blast.

Restaurant worker Emrah Aydinoglu said he was talking on the phone when he heard the explosion.

“I looked out of the window and saw people running,” the 22-year-old said. “People were lying on the ground, already visible from the corner of the street (I was in). They were trying to call (for help), whether it was an ambulance or the police. All of them were shrieking and crying.”

The PKK has fought an insurgency in Turkey since 1984, with the conflict responsible for tens of thousands of deaths.