A bomb rocked a bustling pedestrian avenue in the heart of Istanbul on Sunday, killing six people, injuring several dozen and leaving people terrified to flee the fiery blast or crowd into cafes and shops.
Emergency vehicles rushed to the scene on Istiklal Avenue, a popular thoroughfare lined with shops and restaurants that leads to the iconic Taksim Square. In video posted online, a loud bang was heard and a flash was seen as pedestrians turned and fled.
Turkish President Recep Tayyip Erdogan called the blast a "treacherous attack" and said its perpetrators would be punished. He did not say who was behind the attack, but said he had a "smell of terror" without offering details, adding that he still wasn't sure.

Sunday's explosion was a shocking reminder of the anxiety and security concerns that plagued the Turkish population during the years when such attacks were common. The country was hit by a series of deadly attacks between 2015 and 2017, some by the Islamic State group, others by Kurdish militants seeking greater autonomy or independence.
In recent years, Erdogan has led a sweeping crackdown on militants, as well as Kurdish lawmakers and activists. Amid skyrocketing inflation and other economic woes, Erdogan's anti-terror campaign is a key rallying point for him ahead of next year's presidential and parliamentary elections.
Erdogan, who left for the Group of 20 summit in Indonesia on Sunday, said six people were killed. Vice President Fuat Oktay put the number of injured at 81, with two in serious condition, also saying it appeared to be a terrorist attack.
Justice Minister Bekir Bozdag told pro-government broadcaster A Haber that investigators were concentrating on a woman who sat on a bench next to the blast site for about 40 minutes. The explosion took place minutes after she left it. She said her identity was not yet clear, nor was it clear which group might be behind the attack.
The manager of a restaurant near where the bomb went off said he heard the explosion and saw people running. The dozens of customers inside his restaurant, including women and children, panicked and screamed.
The manager, who spoke on condition of anonymity due to the sensitivity of the situation, said he closed the blinds in his restaurant for fear there might be another explosion and tried to calm customers down. After about 15 to 25 minutes inside, he saw the police on the avenue and organized customers and his staff to leave in small groups.
Numerous foreign governments offered their condolences, including neighboring Greece with which relations are strained. Prime Minister Kyriakos Mitsotakis said he was "shocked and saddened by the news of the heinous attack."
Following attacks between 2015 and 2017 that killed more than 500 civilians and security personnel, Turkey launched cross-border military operations in Syria and northern Iraq against Kurdish militants, while cracking down on Kurdish politicians, journalists and activists at home.
While the Kurdish militants, known as the PKK, are considered a terrorist organization by Turkey, the United States and the European Union, critics say Erdogan has also used sweeping anti-terror laws to stifle free speech.
Most recently, Turkey enacted a controversial “disinformation law” that carries a prison sentence of up to three years for social media users who spread false information about national or international security, public order, or health. Critics have said the article's wording is so vague that it can be used to stamp out dissent.
Police said on Sunday they had identified 25 social media users who shared "provocative content" that could break that law.
In another example of the country's restrictions on the press, Turkey's media watchdog also placed time limits on reporting about Sunday's explosion, a move that prohibits the use of close-up photos and videos of the explosion. and its consequences. The Superior Council of Radio and Television has imposed similar bans in the past, following attacks and accidents.
Access to Twitter and other social networking sites was also restricted.
French President Emmanuel Macron said Sunday that the Istanbul attack came exactly seven years after Islamic State extremists killed 130 people in Paris cafes, the Bataclan theater and France's national stadium.
"On such a symbolic day for our nation, as we think of the victims who fell on November 13, 2015, the Turkish people suffered a heart attack, Istanbul," Macron said. “To the Turks: we share your pain. We are by your side in the fight against terrorism.”