The UN refugee agency says about 8,000 people have fled from Cameroon into Nigeria in the past two weeks because of an upsurge in violence.
The UNHCR said the refugees had trekked through savannah and forests to reach Nigeria.
Some arrived with gunshot wounds.
Fighting between Anglophone separatists and the security forces flared during elections held on Sunday.
More than 600,000 people have been displaced and about 3,000 killed during the conflict which started in October 2017.