BENI, Congo (AP) — A bomb exploded at a restaurant Saturday as patrons gathered on Christmas Day in an eastern Congolese town where Islamic extremists are known to be active.

There was no immediate word on fatalities following the blast in Beni, which struck as people drank beer at tables outside the Inbox restaurant, witnesses told The Associated Press.

Mayor Narcisse Muteba, who is also a police colonel, urged people to return home and stay there as authorities investigated what had happened.

The town has long been targeted by rebels from the Allied Democratic Forces, or ADF, which traces its origins to neighboring Uganda. But an Islamic State affiliate claimed responsibility for two explosions in Beni in June, deepening fears that religious extremism has taken hold there too.

Those explosions included the first known suicide bombing in eastern Congo, a Ugandan man who blew himself up outside of a bar. The Islamic State group’s Central Africa Province later said that the suicide bomber was targeting Christians. The other explosion that day went off inside the Butsili Catholic Parish, wounding 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.