BENI, Congo — A suicide bomber attacked a restaurant and bar Saturday as patrons gathered on Christmas Day, killing at least six in an eastern Congolese town where Islamic extremists are known to be active.

Heavy gunfire rang out shortly after the bomb went off, with panicked crowds fleeing the town’s center.

Saturday’s attack marked the first known time that a suicide bomber has killed victims in eastern Congo, where an Islamic State group affiliate earlier this year took responsibility for a suicide bombing near another bar in Beni who had caused no other casualties.

The latest violence only deepens fear that religious extremism has taken hold in a region already plagued for years by rebels.

Gen. Sylvain Ekenge, spokesperson for the governor of North Kivu, said that security guards had blocked the bomber from entering the crowded bar and so the person instead detonated the explosives at the entrance.

“We call on people to remain vigilant and to avoid crowded areas during the holiday season,” he said in a statement. “In the city and territory of Beni, it is difficult, in these times to know who is who.”

Rachel Magali had been at the restaurant-bar for about three hours with her sister-in-law and several others when she heard a loud noise outside.

“Suddenly we saw black smoke surrounding the bar and people started to cry,” she told The Associated Press. “We rushed to the exit where I saw people lying down. There were green plastic chairs scattered everywhere and I also saw heads and arms no longer attached. It was really horrible.”

Among the dead were two children, according to Mayor Narcisse Muteba, who is also a police colonel. At least 13 other people were wounded and taken to a local hospital.

“Investigations are underway to find the perpetrators of this terrorist attack,” he told The Associated Press.

The town has long been targeted by rebels from the Allied Democratic Forces, or ADF, a group that traces its origins to neighboring Uganda. But in June the Islamic State group’s Central Africa Province said it was behind the suicide bomber and another explosion that same day at a Catholic church that wounded two people.

Residents of the town have repeatedly expressed anger over the ongoing insecurity despite an army offensive and the presence of U.N. peacekeepers in Beni. From 2018 to 2020, the town also suffered through an Ebola epidemic that became the second deadliest in history. More than 2,200 people died in eastern Congo as vaccination efforts were at times thwarted by insecurity in the area.