The head of the U.N. refugee agency says Cameroon is on the front line in the battle against Nigeria's Boko Haram and needs international assistance to support thousands of Nigerians who have fled the Islamic extremists and military operations against them.

The agency says violence in northeastern Nigeria, where Boko Haram militants have seized dozens of towns, has forced some 74,000 people to flee to neighboring Cameroon. Troops from Chad, Niger and Cameroon are now helping Nigeria to combat the militants and win back the towns.

While visiting Cameroon's Far North region on Wednesday, U.N. High Commissioner for Refugees Antonio Guterres said the refugee agency would funnel more resources to Cameroon.