The Nigerian army says it has killed some 100 Boko Haram militants, after repelling an attack on a key town in north-eastern Borno state.

Government forces reportedly seized vehicles and ammunition from insurgents while securing Konduga, 35km (22 miles) from the state capital Maiduguri, on Friday.

The battle followed a warning by elders that Maiduguri was “surrounded”.

Boko Haram has been trying to establish a caliphate in Borno since 2009.

A feared commander known only as Amir is believed to be among the dead Boko Haram militants.

Nigerian troops routed the Boko Haram fighters on Friday morning “after three hours of fierce fighting”, army spokesman Timothy Antigha said in a statement.

The attack on Konduga happened at 05:30 local time (04:30 GMT), he added.

Eyewitnesses said that soldiers and pro-government vigilante fighters appeared in high spirits after the battle, the BBC’s Tomi Oladipo in Lagos says.

The Nigerian military has been trying to boost soldiers’ morale and rallying public support through a social media campaign with the #VictoryForNigeria hashtag, our correspondent says.

Who are Boko Haram?

• Founded in 2002
• Initially focused on opposing Western education – Boko Haram means “Western education is forbidden” in the Hausa language
• Launched military operations in 2009 to create an Islamic state
• Thousands killed, mostly in north-eastern Nigeria – but also attacks on police and UN headquarters in capital, Abuja
• Some three million people affected Declared terrorist group by US in 2013

On Thursday, the Borno Elders Forum (BEF), which represents influential people in the state, released a statement urging the military to “fortify” Maiduguri, the city where Boko Haram was founded in 2002, to prevent an assault “from all directions”.

Boko Haram has captured a string of towns and villages in Borno, as well as territory in neighbouring Adamawa state, forcing thousands of people to flee to the hills.

The Islamist group’s five-year insurgency is seen as the biggest threat to Nigeria’s territorial integrity since the 1967-70 civil war, analysts say.

In recent months it has changed tactics, by holding on to towns in the north-east, where mostly Muslims live, instead of carrying out hit-and-run attacks.