The area around has seen heavy fighting and ambush attacks against soldiers as they escorted civilians from villages into larger towns.

"As of 27 May 2019, a total of 9,432 individuals from Sabon Gari community were moved by the military to Damboa town," the IOM said in a statement.

On Friday, fighters from the Islamic State West Africa Province (ISWAP) faction of Boko Haram opened fire on a column of civilian vehicles under military escort.

Five Nigerian soldiers died in that attack, security sources said, and an unknown number are still missing.

The civilians were moved in four batches since 23 May.

The army has repeatedly moved large numbers of civilians away from areas, ahead of major military offensives.

While some 1,400 people have basic shelter in tents or in school classrooms, over 8,000 are staying in open areas without shelter, IOM said.

Boko Haram's decade-long campaign of violence has killed tens of thousands of people and displaced millions across the region.

The violence has spilled over into neighbouring Niger, Chad and Cameroon, prompting a regional military coalition to battle the jihadist group.