Turkey's president has said the suicide bomber who blew themselves up at a wedding party, killing at least 51, was a child aged as young as 12 years old.

Speaking live on national television in front of Istanbul's city hall, Recep Tayyip Erdogan said the attacker was aged between 12 and 14 and had wounded 69 people, 17 of which were in a critical condition.

"It was clear that Daesh had such an organization in Gaziantep or was attempting to make room for itself in recent times," President Erdogan said, using an alternative acronym for Isis.

"Many intensive operations were conducted, are being conducted. Of course our security forces will be conducting these operations with even greater intensity."

suicide attack at wedding in Gaziantep

The bride and groom were not in a life-threatening condition and were undergoing treatment, the Anadolu news agency reported. The groom's sister and uncle were among the dead.

People were dancing when the explosion ripped through the celebrations on Satuday in the city of Gaziantep, in the volatile south east near the border with Syria.

Earlier, President Erdogan said Isis were likely behind the attack.

The prosecutor's office said a destroyed suicide vest had been discovered at the scene.

Celebrations were ending at the traditional henna night party, when guests have decorative paint applied to their hands and feet. Some families had already left when the bomb went off but women and children were among the dead, witnesses said.

The late-night attack happened in Gaziantep in the south east (Getty)

Blood stains and burns marked the walls of the narrow lane where the blast hit while women in white and checkered scarves cried while waiting outside the morgue waiting for word on missing relatives.

"The celebrations were coming to an end and there was a big explosion among people dancing," said 25-year-old witness Veli Can. "There was blood and body parts everywhere."

At least 12 people were buried on Sunday, but other funerals would have to wait because many of the victims were unidentifiable.

DNA forensics tests would be needed to identify them, security sources said.

People were dancing when the bomb exploded (Getty)

A pro-Kurdish political party condemned the attack on the Kurdish wedding party, blaming Isis for the attack.

The People's Democratic Party, or HDP, said "we condemn and curse the ones who launched this attack, both the forces and ideology behind their actions".

Turkish authorities issued a media blackout on coverage of the attack until the investigation is completed.

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Turkey is still in a state of emergency following an attempted coup on 15 July, which Ankara blames on US-based Muslim cleric Fethullah Gulen. He has denied the charge.

Three suspected Isis suicide bombers killed 44 people at Istanbul's main airport in June, which was then the deadliest in a string of attacks in Turkey this year.

In October last year, suicide bombers killed at least 95 people attending a rally of pro-Kurdish and labour activists outside Ankara's main train station.

Violence flared up again this week in the predominantly Kurdish southeast, with separate bombings killing at least 10 people, mostly police and soldiers, in an esclation officials blamed on the the Kurdistan Workers' Party (PKK).