At least 30 people have been killed in a triple suicide bombing outside a video hall in north-eastern Nigeria, emergency service officials say.

Another 40 were injured in the attack in Konduga village in Borno State, the officials said.

There are conflicting reports about whether the blast occurred while people were watching football or a film.

Militant Islamist group Boko Haram is being blamed for the attack. There was no immediate comment from the group.

Formed in Borno State, the group has waged a brutal insurgency across the north-east for a decade.

Ali Hassan, leader of a self-defence group in Konduga, told AFP news agency that the owner of the hall had prevented one bomber from entering.

"There was a heated argument between the operator and the bomber who blew himself up," he said.

Two other attackers who were nearby then set off their devices.

The number of deaths was so high because emergency services arrived late to the site of the blast and were not adequately equipped to deal with such a large number of wounded people, Usman Kachalla, head of operations at the State Emergency Management Agency (Sema) told AFP.

Video halls are common across northern Nigeria. They are usually rudimentary buildings where people pay a small fee to watch football matches or films.

Boko Haram has targeted them on several occasions, saying they are unIslamic.

Konduga has been targeted before. In July 2018, eight people were killed after a suicide bomber detonated explosives in a mosque.

At least 27,000 lives have been lost and about two million people forced to flee their homes in the conflict with Boko Haram.