The reign of terror by Boko Haram militants in northern Nigeria is forcing 800 people to flee every day and has claimed over 3,000 lives in the last year, a report showed on Thursday.

The Internal Displacement Monitoring Centre (IDMC) said that a total of 3.3 million Nigerians have now been driven from their homes by Boko Haram attacks and other violence.

The group's relentless attacks on civilians -- including the high-profile kidnapping of scores of schoolgirls earlier this year -- could have implications for the wider region, with West Africa's wider security increasingly at risk, the IDMC warned.

"The group is growing in its ambition, capability and reach, creating fears that it will become a regional destabilising force, on par with Kony's Lord's Resistance Army in Central Africa," Alfredo Zamudio, director of IDMC, said in a statement.

"As the government struggles to contain the group's southward spread towards Abuja, questions to the future of regional stability have been raised which have weakened Nigeria's relations with Cameroon, Niger and Chad," he added.

In its report, the IDMC, which is run by the Norwegian Refugee Council, said despite counterinsurgency operations and the imposition of a state of emergency in the region by the Nigerian government in May 2013, Boko Haram attacks have escalated in frequency and impact.

It said that at least 3,000 people have been killed since the state of emergency was imposed, based on figures from the United Nations which ran up to March this year.

At least 250,000 fled their homes over the same period, the IDMC said, using official Nigerian figures published by the UN.

The total displacement figure of 3.3 million, which includes those fleeing Boko Haram as well as communal violence in various regions, was provided by the Nigerian National Commission for Refugees.

"Suffering of civilians is the terrible dividend of this violent reality, and children are particularly on the front line," said Zamudio.

"We are hearing reports of the brutal killings and maimings, forced recruitment and abduction of children, rape and sexual violence, forced marriage of young girls and children now orphaned as a result of being separated from their parents during flight," he added.

The figures come after reports that hundreds of people may have been killed in a suspected Boko Haram attack in the northeast of the country on Tuesday.

Gunmen laid siege to four villages, razing homes, churches and mosques, killing many, according to one lawmaker, although there has been no independent verification of the claim.

The IDMC said that the local economy has also been seriously affected by the violence, which could have devastating consequences in the next few months.

Over 60 percent of farmers in the north were displaced just before the start of the planting season, sparking worries of severe food insecurity and escalating food prices, it said.