DAKAR, Senegal (AP) — A suspected Islamic extremist in southeastern Niger detonated his explosives when confronted by a policeman Sunday morning, killing the officer and wounding civilians in a town targeted numerous times by jihadists this year.

There was no immediate claim of responsibility though suspicion immediately fell upon Boko Haram, the Nigeria-based extremist group that has pledged allegiance to the Islamic State and carried out scores of attacks in neighboring Niger, Cameroon and Chad in recent months.

Aboubacar Halilou said Sunday that he was coming out his house in the town of Diffa around 8 a.m. when he saw four young men walk past.

"They had their hands on their stomachs, walking in the rain in the direction of the police station," Halilou told The Associated Press. "A police officer tried to approach these young men before they arrived at the station but when he came closer one of the men detonated his explosives." The policeman was killed, said Halilou.

"The three others started to flee, and another officer who was there shot and killed one of them at the scene. The two others ran in an effort to reach town. There was a real chase but the officers finally caught them," he said.

It was not immediately clear how many civilians were wounded or if any were killed.

Boko Haram members have repeatedly struck Diffa in neighboring Niger over the past year because Niger's military is among those taking part in a regional effort to defeat the extremists. Niger is also home to more than 138,000 refugees who have fled Boko Haram's attacks in Nigeria, according to U.N. figures.

Associated Press writer Krista Larson contributed to this report.