ISTANBUL - Turkey’s president on Sunday blamed the Islamic State of Iraq and Syria (ISIS) for the bombing of an outdoor wedding party inthe southeast that killed 51 people and wounded dozens of others.

Officials say Saturday’s attack in Gaziantep, near Syria’s border, appeared to be a suicide bombing. It appeared to be just a regular wedding and it wasn’t immediately clear why it was targeted. The BBC reports the bomber appears to have attacked the Kurdish wedding as revelers danced in the streets.

The remains of a suicide vest have been recovered at the site, according to the state-run Anadolu Agency, citing a statement by the chief public prosecutor’s office.

Women mourn as they wait in front of a hospital morgue in the Turkish city of Gaziantep, after a suspected bomber targeted a wedding celebration in the city, Turkey, August 21, 2016. REUTERS/Osman Orsal

President Recep Tayyip Erdogan issued a statement early Sunday denouncing the “heinous” bombing and saying that ISIS was “the most likely perpetrator of the Gaziantep attack.”

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Erdogan said it appears ISIS has an operation of some kind already going in the city.

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

He said the bomber was between 12 and 14 years old.

The initial death toll was 30 killed and 94 wounded. Later, the Gaziantep governor’s office raised the toll to 51. Erdogan said 69 people were wounded, with 17 of them in critical condition. It is the deadliest extremist attack of 2016.

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. A dual suicide bombing blamed on ISIS at a peacerally​ in Turkey’s capital, Ankara, in October killed 103 victims.

The attack comes as the country is still reeling from lastmonth’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.

“These bloodthirsty organizations and the powers behind them have neither the will nor power to silence the calls to prayer, lower the flag, divide our motherland and break up our nation,” he added.

Earlier this week, a string of bombings blamed on the PKKthat targeted police and soldiers​ killed at least a dozen people. A fragile, 2.5 yearlong peace process between the PKK and the government collapsed last year, leading to a resumption of the three-decade-long conflict.

The two sides have engaged in violent attacks and reprisals​ with little sign of a negotiated peace returning. It’s unclear how the wedding attack will affect the 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.

Opposition parties have also denounced the attack. The main opposition Republican People’s Party will be holding an emergency meeting in the late afternoon and a delegation was being sent to Gaziantep by the Nationalist Movement Party. Supporters of the pro-Kurdish People’s Democracy Party will be holding a protest against the attack in Istanbul.

Foreign governments have also condemned the attack, with statements issued by the U.S., Sweden, Greece, France, Bahrain, Qatar and Jordan.

Police sealed off the site of the explosion and forensic teams moved in.

Hundreds of residents had gathered near the site chanting “Allah is great” as well as slogans denouncing attacks.

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