Suspected Boko Haram gunmen have killed at least 32 people in three separate attacks in northeast Nigeria, including at a theological college, a local government official and residents have said.

The co-ordinated attacks in Adamawa state late on Wednesday came just a day after armed fighters were blamed for killing 59 people, most of them children, as they slept at a boarding school in Yobe state.

Maina Ularamu, the chairman of the Madagali local government area in Adamawa, said "a large number of militants carried out three separate attacks on Shuwa and Kirchinga in my local government area and on Michika in neighbouring Michika (district)".

The gunmen divided themselves into three groups and separately attacked the three locations Maina Ularamu, chairman of the Madagali local government area

"The gunmen divided themselves into three groups and separately attacked the three locations," he told AFP news agency.

In Shuwa, several buildings were burnt, including a Christian theological college and a section of a secondary school.

A local resident, Kwaje Bitrus, said three bodies were recovered from the seminary and a total of 20 were killed in and around the village.

In Kirchinga, Samuel Garba said the gunmen were all dressed in military uniform - a tactic used by the armed fighters in previous, similar attacks.

"The gunmen... killed eight people in our village and burnt many houses," he added.

"Four people have so far been confirmed dead in Michika," said Abdul Kassim, who lives in the village.

The dead were a young boy and three security guards, he added.

The northeastern states of Adamawa, Yobe and Borno have been under emergency rule since last May, when the military launched an offensive to stamp out the armed rebellion, which has killed thousands since 2009.

Hundreds of thousands displaced

The UN said on Thursday that nearly 300,000 people, more than half of them children, had fled their homes in the three states from May last year to this January because of the violence.

Residents in Michika described earlier how people fled to the nearby foothills when the attackers arrived in four-wheeled drive trucks and on motorcycles.

Michika resident Abdul Kassim said militants arrived at about 9.30pm (8.30pm GMT) on Wednesday, "armed with RPGs and explosives which they hurled indiscriminately at homes and public buildings".

The attack reportedly lasted for more than four hours. Various residents said four banks were razed, as well as hundreds of shops, a police station, government buildings and dozens of homes.

One witness said that about 90 percent of all businesses had been destroyed. The military and police declined to comment when contacted by AFP.

The top military commander in Adamawa state last week ordered the complete closure of the border with Cameroon to block the movements of fighters and weapons.

The ongoing military offensive has failed to crush the armed struggle and nearly 300 people have been killed in a range of attacks already this year.