Some parts of northeast Nigeria that have been devastated by seven years of violence from the Islamist Boko Haram insurgency could be suffering from famine, AFP reports citing experts monitoring the situation.

The U.S.-based Famine Early Warning Systems Network (FEWS NET) said in a briefing note on its website Thursday, July 7 that more than three million people in the region were in need of urgent assistance.

Borno state, which has been the worst hit by the conflict since 2009, was singled out for particular concern after Nigeria's health ministry recently declared a "nutrition emergency".

FEWS NET said that "information from recent rapid assessments, although limited and not statistically representative, also raises the possibility that a famine... could be occurring in the worst affected and less accessible pockets of the state".

Famine is declared where at least 20 percent of an area's population faces an extreme lack of food, at least 30 percent of children are acutely malnourished and the crude death rate exceeds 2/10,000 per day, it added, according to AFP.

Aid agencies have been increasingly warning about the dire humanitarian situation in Borno, which has borne the brunt of fighting between Boko Haram insurgents and government forces that has left at least 20,000 dead since 2009.

More than 2.6 million people have been made homeless, two million of them within Nigeria, fleeing to makeshift camps or being taken in by friends, families or distant relatives.