The United Nations Refugee Agency says humanitarian conditions are worsening and insecurity is increasing in Niger's southeast Diffa region as thousands displaced by violence are forced to resettle.

It said Tuesday that a succession of violent incidents and suicide attacks by the Nigeria-based Islamic extremists of Boko Haram have occurred in recent months near villages and areas where some 157,000 people have set up makeshift camps to flee the violence.

The violence has forced at least two large markets to close since April, hurting the local economy as farmers, herders, fisherman and traders have lost their main source of income to the insecurity.

The agency says more than 2.7 million people have been displaced in the area around Lake Chad because of violence linked to the Boko Haram extremists.