Turkey's president has blamed the Islamic State in Iraq and Syria group for the bombing of an outdoor wedding party in the southeast that killed 51 people and wounded many others.
Officials say Saturday's attack in Gaziantep, near Syria's border, appeared to be a suicide bombing.
President Recep Tayyip Erdogan issued a statement early Sunday saying that ISIS was "the most likely perpetrator of the Gaziantep attack."
Turkey has been rocked by a wave of attacks in the past year that have either been claimed by Kurdish militants linked to the outlawed Kurdistan Workers' Party — known by its acronym PKK — or were blamed on ISIS. In June, suspected ISIS militants attacked Istanbul's main airport with guns and bombs, killing 44 people.
The attack comes as the country is still reeling from last month's failed coup attempt, which the government has blamed on U.S.-based Muslim cleric Fethullah Gulen and his followers. Gulen denies any involvement.
Erdogan said there was "absolutely no difference" between ISIS, Kurdish rebels and Gulen's movement, calling them terrorist groups.
Earlier this week, a string of bombings blamed on the PKK that targeted police and soldiers killed at least a dozen people. A fragile, two-and-a-half-year-long peace process between the PKK and the government collapsed last year, leading to a resumption of the three-decade-long conflict.
In Gaziantep, Deputy Prime Minister Mehmet Simsek and the country's health minister visited the wounded and inspected the site of the attack.
"This is a massacre of unprecedented cruelty and barbarism," he told reporters. "We ... are united against all terror organizations. They will not yield."
Prime Minister Binali Yildirim condemned the bombing, which he said turned "a wedding party into a place of mourning" and he vowed to prevail over the "devilish" attacks.
Police sealed off the site of the explosion and forensic teams moved in. Hundreds of residents gathered near the site chanting "Allah is great" as well as slogans denouncing attacks.