Suspected Boko Haram gunmen opened fire on a military convoy at the weekend in central Nigeria’s Kogi state, injuring four soldiers, a senior military source said Tuesday.

The convoy of 850 soldiers came under fire late Sunday near the town of Okene as they drove towards the Kogi state capital Lokoja, the source said.

The troops were to undergo counter-terrorism training for deployment to the northeast to fight Boko Haram Islamists, he said.

They “came under fire… from gunmen we strongly suspect to be Boko Haram terrorists,” said the source, who requested anonymity because he was not authorised to discuss the incident.

Nigerian soldiers involved in counter terrorism

According to the source military insiders could have tipped off the attackers on the confidential troop movement.

Meanwhile Tuesday, Nigerian troops were battling Boko Haram insurgents who stormed Konduga town in northeastern Borno state, according to some military sources.

They said the militants were “on a revenge mission after the heavy casualties they recorded last Friday.”

On Friday, around 100 insurgents met stiff resistance from troops and members of a civilian vigilante group known as the Joint Task Force.

An army spokesman said the troops prevailed after about three hours of “fierce fighting”, adding that the insurgents suffered heavy casualties.

“From the information we have so far, the insurgents were armed to the teeth. They have mortars, anti-aircraft missiles, rocket-propelled grenades and assorted guns with a cover from armoured personnel carriers,” a military source told AFP of the fighting in Konduga.

“Our men are engaging the terrorists,” he said, adding that their “ultimate target” is the state capital Maiduguri some 35 kilometres (22 miles) away.

Boko Haram have made rapid territorial gains in Borno as well as nearby Yobe and Adamawa in recent weeks that Nigeria’s military has acknowledged posed a threat to the country’s sovereignty.

The jihadists say they want to establish an Islamic caliphate in northern Nigeria and have killed thousands since launching their campaign in 2009.