Text updated Sunday 11.32 am - A bomb attack on an outdoor wedding party in south-eastern Turkey that killed 50 people and wounded dozens of others was the work of IS, the country's president said.
Officials said yesterday's attack in Gaziantep, near Syria's border, appeared to be a suicide bombing.
President Recep Tayyip Erdogan issued a statement today saying that IS was "the most likely perpetrator of the Gaziantep attack".
The initial death toll was 30 killed and 94 wounded. Later, the Gaziantep governor's office raised the toll to 50, without giving a number of wounded, according to the state-run Anadolu Agency.
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 IS.
In June, suspected IS 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 US-based Muslim cleric Fethullah Gulen and his followers. Gulen denies any involvement.
Mr Erdogan said there was "absolutely no difference" between IS, 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 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 organisations. 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.