Police have arrested 46 suspects after six people were killed in an attack on a bustling pedestrian avenue in Istanbul on Sunday.
Among them is Syrian woman Ahlam Albashir, who is suspected to have planted the bomb.
Police say that during an initial questioning, she said she was trained by Kurdish militants in Syria and entered Turkey through northwest Syria’s Afrin region, according to Reuters news agency.
Several dozen people were also were wounded in the explosion on Istiklal Avenue, a popular thoroughfare lined with shops and restaurants that leads to the iconic Taksim Square. A government ministry worker and his young daughter were among the dead.
Turkey's government blamed Kurdish militants on Monday for the blast.
“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.
Turkey’s president Recep Tayyip Erdogan said the explosion was caused by a “heinous” bomb attack. He said the explosion “smells like terrorism”, although he said investigations were still underway.
Nobody has yet claimed responsibility for the blast.
Justice Minister Bekir Bozdag told pro-government broadcaster A Haber on Sunday that investigators were focusing on a woman who sat on a bench near the scene of the blast for about 40 minutes. The explosion took place just minutes after she left.
Local outlets report she is the woman who has now been arrested by police.
Mr Soylu said evidence in Sunday’s bombing 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,” he 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.
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 out 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 PKK has fought an insurgency in Turkey since 1984, with the conflict responsible for tens of thousands of deaths
Mr Erdogan told a news conference on Sunday: “Efforts to defeat Turkey and the Turkish people through terrorism will fail today just as they did yesterday and as they will fail again tomorrow.
"Our people can rest assured that the culprits behind the attack will be punished as they deserve.
"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.”
Footage posted online showed flames erupting and a loud bang, as pedestrians turned and ran away.
“When I heard the explosion, I was petrified, people froze, looking at each other. Then people started running away. What else can you do,” said Mehmet Akus, 45, a worker in a restaurant on Istiklal told Reuters news agency.
“My relatives called me, they know I work on Istiklal. I reassured them,” he said.
The Turkish Red Crescent said blood was being transferred to nearby hospitals in the wake of the explosion.
Condemnations of the attack and condolences for the victims have been paid by several countries, including Greece, Egypt, Ukraine, Azerbaijan and Pakistan.
European Council President Charles Michel said on Twitter he had sent condolences to victims after the “horrific news".
The avenue is a crowded thoroughfare popular with tourists and locals, lined by shops and restaurants.
Turkey was hit by a string of bombings between 2015 and 2017 that left more than 500 civilians and security personnel dead.
Some of the attacks were perpetrated by the Islamic State group, while others were executed by Kurdish militants who have led a decades-long insurgency against the Turkish state for increased autonomy or independence.
