LAGOS, Nigeria

At least 12 people were killed on Wednesday after an improvised explosive device buried under a road in Nigeria's restive northwest Zamfara State detonated, according to locals.

Aliyu Yusha'u, a community leader, told Anadolu that the blast occurred as a commercial bus passed over explosives believed to have been buried under a major road in Yar Tasha village in the state's central Maru area.

"The explosion affected the passengers. A total of 12 died, and others were injured," he said over the phone.

The police had not released an official statement on the incident as of 7.15 p.m. local time (1812GMT).

Ibrahim Jauro, a local official in Maru, said the bus was transporting passengers to the nearby town of Dansadau when it passed over the explosives.

This was the second incident in the area in the past week, coming after another improvised explosive device went off as a car passed over it on Sunday, killing the driver.

Attacks by terrorists and armed groups known locally as bandits have been on the increase in Zamfara. Authorities have responded by deploying special military forces to the area.