In northern Nigeria, a gunbattle between rebels and security forces has left 10 police officers dead, authorities said Tuesday. The clash occurred on Monday in the Sakaba council area of Kebbi state. According to police spokesperson Bashir Usman, two civilians and 17 rebels were also killed.

Usman said the rebels were heavily armed and riding on motorcycles when they were intercepted by security forces. They were seen close to the border with Zamfara state, where armed gangs who frequently raid Nigerian towns and villages are concentrated.

“Tragically, we lost 10 gallant police personnel in the engagement, while two others sustained injuries and are receiving medical attention,” the police spokesman said.

The attack is the latest in a cycle of violence in Africa’s most populous country, where gangs compete for territory and control of natural resources in villages where they outnumber the country’s overstretched security forces. Dozens have been killed in recent weeks across the north, and security forces are often targeted.

The U.S. government is providing military support to Nigeria under an agreement it says aims to protect Nigerian Christians, though much of that support is restricted to logistics and intelligence-gathering at the heart of the violence in the north.