A bomb attack targeting an outdoor wedding party in southeastern Turkey killed at least 30 people and wounded 94 others, the Turkey authorities said Sunday.

Deputy Prime Minister Mehmet Simsek said the “barbaric” attack in the city of Gaziantep, near the border with Syria, on Saturday appeared to be a suicide bombing. Other officials said it could have been carried out by either Kurdish militants or Islamic State extremists.

Photographs taken after the explosion showed several bodies covered with white sheets as a crowd gathered nearby.

Early on Sunday, the Gaziantep governor’s office raised the death toll to 30 from 22. It said the number of wounded remained at 94.

Turkey has been rocked by a wave of attacks in the past year that have been claimed by Kurdish militants linked to the outlawed Kurdistan Workers’ Party — known by its acronym, P.K.K. — or have been attributed to the Islamic State, also known as ISIS or ISIL. In June, assailants suspected of being Islamic State militants attacked Istanbul’s main airport with guns and bombs, killing more than 40 people.

The attack on the wedding came as the country was still reeling from a failed coup attempt last month, which the government has accused Fethullah Gulen, a Muslim cleric based in the United States, and his followers of plotting.

Earlier this week, a string of bombings blamed on the P.K.K. that targeted the police and soldiers killed at least a dozen people. A fragile peace between the group and the government collapsed last year, leading to a resumption of the three-decade conflict.

In an interview with NTV television, Mr. Simsek called the bombing a “barbaric attack” and said multiple terrorist groups were targeting Turkey. “ God willing, we will overcome,” he said.

Mr. Simsek later went to Gaziantep along with the country’s health minister to visit the wounded and see the site of the attack.

“This is a massacre of unprecedented cruelty and barbarism,” he told reporters there.

He said it was too soon to say who was behind the attack.

Prime Minister Binali Yildirim condemned the bombing, saying it had turned “a wedding party into a place of mourning.”

“No matter what this treacherous terror organization is called, we as the people, the state, and the government will pursue our determined struggle against it,” he said.

A brief statement from the governor’s office in Gaziantep said the bombing struck the wedding in the Sahinbey district at 10:50 p.m. The statement condemned the “treacherous” attack, but did not provide additional details.

Mehmet Tascioglu, a local journalist, said on NTV television that a huge explosion could be heard in many parts of the city.

In Gaziantep, the police sealed off the site of the attack and forensic teams began investigating. Hundreds of residents gathered near the site, chanting “God is great” as well as slogans denouncing terrorist attacks.