MAIDUGURI, Nigeria (AFP) - More than 70 people were killed in two separate attacks in northeast Nigeria, police and state authorities said on Monday, with suspicions falling on the banned Islamist militant group Boko Haram.

The attacks on Sunday - one on a busy market in Borno state, killing 45, and the other in neighbouring Adamawa, which left at least 26 dead - came just a week after a change of the guard at the top of Nigeria's military.

New chief of defence Air Marshall Alex Badeh, who comes from Adamawa, had said he wanted a swift end to the bloody insurgency, which has claimed thousands of lives since 2009.

But the latest attacks will likely renew calls for a more effective strategy, possibly considering non-military means such as dialogue or wider development schemes to prevent radicalisation in the impoverished north.

Adamawa state spokesman Ahmad Sajo told the Agence France-Presse (AFP): "From information from the police authorities, 26 people were killed in the attack, including two policemen, who mistook the attackers for soldiers because they were wearing military uniforms.

"Seventeen of the victims were shot dead... At the moment we don't know who the attackers were. We're waiting for that information from the security agencies."

An unspecified number of injured were being treated in hospital, he added.

Police had earlier said at least 45 people were killed and 26 others wounded in the Borno attack. "So far, we have 45 dead and 26 injured... but the figures could increase as our men are still in the village searching for more casualties," state police commissioner Lawan Tanko told AFP.

The attack happened at about 5pm (10am the next day, Singapore time) on Sunday when gunmen disguised as traders stormed Kawuri, in the Konduga area of Borno, 37 km from the state capital, Maiduguri.

Witnesses said the gunmen arrived in four-wheel-drive vehicles and opened fire with machine guns before setting off homemade bombs that destroyed houses and other property.

Mr Tanko, who blamed the attack on "the Boko Haram sect", said he could not confirm that explosives were used but a specialist bomb disposal team had been sent in to search for unexploded devices.

Thousands of civilians have died since the start of the Boko Haram insurgency in 2009 and the military response to it.

Nigeria's military claims it has been successful in forcing the Islamists out of towns and cities and into more remote rural areas near the border.

But attacks have continued, forcing thousands to flee to neighbouring Cameroon, Niger and Chad and prompting claims that a purely military strategy to end the conflict is not working.

Kawuri was attacked in October last year when suspected Boko Haram fighters clashed with a civilian vigilante group, leaving 10 dead and dozens of shops and homes razed.

Emergency relief and disaster agencies meanwhile said they were assisting people affected by the Adawama incident.

"The main details are sketchy because it's a security issue," said National Emergency Management Agency (NEMA) spokesman Abdulkadir Ibrahim.

"The Red Cross and Adamawa State Emergency Management Agency have mobilised. They are on the ground trying to provide some relief for those who lost their houses."

Adamawa has also been under emergency rule since May but has been relatively calm compared to its northern neighbour Borno.

Nigeria's President Goodluck Jonathan this month replaced his most senior military brass days after a car bomb ripped through a crowded market in Maiduguri, killing 19.

Boko Haram earlier claimed an attack in December on military installations in Maiduguri.