President Erdogan said the child was aged between 12 and 14
A child suicide bomber has been blamed for killing at least 51 people in a "barbaric" blast at a wedding in the Turkish city of Gaziantep.
Another 69 were injured in the explosion - 17 of them "heavily" - in what a regional official in southern Turkey described as a "terror attack".
In a live nationally-televised address in front of Istanbul's city hall, Turkey's President Recep Tayyip Erdogan said: "The explosion was the result of a suicide bomber aged between 12 and 14 who either detonated (the bomb) or others detonated it."
He also repeated what he had said earlier - that Islamic State militants were the "likely perpetrator(s)" of the bombing.
"It was clear that Daesh had such an organisation in Gaziantep or was attempting to make room for itself in recent times. Many intensive operations were conducted, are being conducted."
"Of course our security forces will be conducting these operations with even greater intensity."
Witness Veli Can (25) said: "The celebrations were coming to an end and there was a big explosion among people dancing. There was blood and body parts everywhere."
A bus driver who took some of the guests to the wedding said: "This attack was deplorable - how did they do such a thing?".
At least 12 victims have already been buried but other funerals have been delayed because identification is difficult.
The bride and groom - Besna and Nurettin Akdogan - are among those being treated in hospital but are not in a life-threatening condition, according to the state-run Anadolu news agency.
The groom's sister and uncle are reportedly among the dead.
Deputy Prime Minister Mehmet Simsek visited the site of the attack, which he described as "a massacre of unprecedented cruelty and barbarism".
Gaziantep is just 37 miles north of the Syrian border.
As well as a home to many Syrians fleeing their country's civil war, there are fears it has also started to become a home for jihadists.
Some security officials have blamed Kurdish militants for the attack.
But the area of the city where the wedding was held is said to have a large number of Kurdish residents and the pro-Kurdish Peoples' Democratic Party (HDP) said the wedding was for one of its members.
Kurds are also playing a major role in fighting Islamic State in Syria, adding to speculation that IS was behind the attack.
Mr Erdogan said the aim of the bombing was to divide Turkey's different groups and "spread incitement along ethnic and religious lines".
"Our country and our nation have again only one message to those who attack us - you will not succeed," he added.
Turkey has suffered a series of attacks claimed by IS or Kurdish militants linked to the outlawed Kurdistan Workers' Party, known by its acronym PKK.
Last month the country was shaken by an attempted coup launched by rogue elements of the military.
Thousands have since been arrested or sacked in the military, police, civil service, judiciary and academia in a crackdown on what President Erdogan calls a vast terrorist conspiracy.
More than 200 people were killed in the failed coup that Mr Erdogan says was organised by a former ally, exiled Islamic cleric Fethullah Gulen.
Three suspected IS suicide bombers also killed 44 people at Istanbul's main airport in July.