YAOUNDE, CAMEROON - Boko Haram Islamists killed five Cameroonian soldiers and a civilian in an attack in the far north of the country, the defense ministry said Tuesday.

The attack took place on Monday night near the border with Nigeria, where operations by the Islamist group have been on the rise.

Three soldiers and one civilian were also wounded in the attack, the statement read on state radio said.

A group "of heavily armed terrorists of the Boko Haram sect, aboard several light tactical vehicles, attacked the command post ... near Zigue," a few kilometers from the border with Nigeria, the statement said.

Some militants were also killed, the statement added, without elaborating.

"Troops remain on high alert throughout the far north and across the border to prevent further attacks," it said. The group appears to have "regained strength following internal restructuring," it added.

Members of Boko Haram and a splinter group, the Islamic State in West Africa (ISWAP), have been mounting increasingly deadly attacks against security forces and civilians in the far north of Cameroon, as well as in neighboring Nigeria, Niger and Chad.

They frequently abduct civilians, especially women and children.

Boko Haram fighters killed eight Cameroonian soldiers on Saturday in Sagme, a few dozen kilometers from the border with Nigeria.

Their insurgency began in 2009 in northeastern Nigeria before spreading through the region.

Since then, more than 36,000 people - mainly in Nigeria - have been killed, and three million forced to flee their homes, according to U.N. estimates.

In 2016, the group split into two branches: the faction led by its long-time leader, Abubakar Shekau, and ISWAP, affiliated with the Islamic State group.

Boko Haram confirmed in mid-June that Shekau had been killed in fighting with ISWAP.