Turkish President Recep Tayyip Erdogan says that a child suicide bomber carried out the August 20 attack on a wedding party in the southeastern city of Gaziantep that left 51 people dead and dozens of others wounded.
"The explosion was the result of a suicide bomber aged between 12 and 14 who either detonated [the bomb] or others detonated it," Erdogan told an August 21 news conference in Istanbul.
He also repeated his earlier assertion that information indicated that the attack, the deadliest in Turkey so far this year, was carried out with the involvement of the extremist Islamic State (IS) group.
"It was clear that Daesh had such an organization in Gaziantep or was attempting to make room for itself in recent times," Erdogan said, using an alternative acronym for the extremist group.
No group has claimed responsibility.
Erdogan said that 69 people were wounded in the attack, 17 of them seriously.
He added that the aim of such attacks was to "spread incitement along ethnic and religious lines" in Turkey.
"Wherever this terror comes from, it doesn't change it for us. As a nation, we will use our full strength, united, shoulder to shoulder, to fight against terror like we did on July 15," Erdogan said, referring to the failed coup attempt against him last month.
Gaziantep is located some 64 kilometers from the Syrian border.
Turkey's majority-Kurdish southeast has been hit by several deadly blasts over the past year, linked either to Kurdish separatist militants or the IS group.
Prime Minister Binali Yildirim denounced the "devilish" attack, saying it turned "a wedding party into a place of mourning."
The bombing was also condemned by Turkish opposition parties and numerous foreign governments, including the United States, France, Greece, Sweden, Jordan, Qatar and Bahrain.
