NIAMEY, Niger — Gunmen attacked a prison in Niger that holds jihadists early Monday and were repelled by security forces who killed an attacker, Niger’s interior and public security minister said.

Two guards were also wounded in the attack around 4:30 a.m. at Koutoukale prison, which holds prisoners from extremist groups from northern Mali and Nigeria’s Boko Haram, said Mohamed Bazoum. The prison is about 40 kilometers (25 miles) from the capital, Niamey.

The unknown number of assailants were repulsed, and one was killed, he said.

“The attackers were wearing explosive belts, proving the terrorist nature of the operation,” he said, adding that Niger forces are pursuing the assailants who fled after the attack.

No group claimed responsibility for the attack, which comes days after suspected extremists abducted an American aid worker, killing two people before fleeing with the man toward the border with Mali.

Landlocked Niger is surrounded by instability and threats of extremist violence by Nigeria’s Boko Haram insurgents to the south, al-Qaida-linked Islamic extremists in Mali to the west and jihadists in Libya to the north.

In 2013, Boko Haram attacked a prison in Niamey, killing two guards and freeing more than 20 inmates.

AP writer Baba Ahmed in Bamako, Mali contributed to this report.