At least six people have been killed and 81 wounded in an explosion in a busy area of central Istanbul.

Qatar’s Amir Sheikh Tamim bin Hamad Al Thani offered his condolences to Turkey after a powerful explosion rocked Istanbul’s busy commercial area of Istiklal on Sunday, killing six people and injuring 81.

Sheikh Tamim made the comments during a phone conversation with Turkey’s President Recep Tayyip Erdogan on Sunday, just hours after the bomb attack struck the tourist-heavy area.

The Qatari leader also reiterated Doha’s firm stance regarding the rejection of violence, terrorism, and targeting of civilians and innocents.

He also affirmed Qatar’s stand by Turkey and its people as well as its support for all the measures it takes to maintain its security and stability.

Condemnations of the incident from a number of nations, including Azerbaijan, Egypt, France, Greece, Iran, Italy, Pakistan, Ukraine, the United Kingdom, and the United States, as well as condolences for the victims, poured in.

Greece “unequivocally” denounced the explosion and expressed condolences, while the US said it stood “shoulder-to-shoulder with our NATO ally in countering terrorism”.

“We share your pain… We are with you in the fight against terrorism,” French President Emmanuel Macron wrote in a tweet in Turkish.

Ukrainian President Volodymyr Zelensky, also writing in a tweet in Turkish, said: “The pain of the friendly Turkish people is our pain.”

Turkish police have detained 22 people in connection with the blast.

Vice-President Fuat Oktay earlier said the bombing was thought to be a terrorist attack carried out by a woman, with the Turkish president saying the offenders would face punishment.

Before leaving for the G20 conference in Indonesia, Erdogan said that preliminary information suggested that a “woman had played a part” in the assault.

He denounced during a news conference in Istanbul the “vile attack” and claimed that “the smell of terror” is around, reports said.

Soylu attributed Sunday’s explosion on Istiklal Avenue to the banned Kurdistan Workers Party (PKK), adding: “Our assessment is that the order for the deadly terror attack came from Ayn al-Arab [Kobane] in northern Syria,” where he said the organisation’s Syrian headquarters is located, according to reports.

He also stated that 81 people had been injured, with two of them in “critical condition,” and that the death toll had increased from six to eight. “We will retaliate against those who are responsible for this heinous terror attack,” he warned.

No group has claimed responsibility for the bombing yet.

Kurdish separatists, ISIL (ISIS), and other organisations have previously targeted Istanbul and other Turkish cities, including in a flurry of attacks in 2015 and 2016.

These include the two explosions that occurred in December 2016 outside an Istanbul football stadium, leaving 155 people injured and 38 dead.

An offshoot of the PKK, which has been fighting for Kurdish self-rule in southeast Turkey since the 1980s and is considered a terrorist organisation by Turkey, claimed responsibility for the attack.

The PKK, which is frequently the focus of Turkish military operations, is also at the centre of a dispute between Sweden and Turkey, which has been preventing Stockholm’s membership in NATO since May on the grounds that Stockholm has been lenient toward the Kurdish group, reports detailed.