Jihadists linked to the Islamic State have attacked a UN base and overrun a humanitarian hub in northeastern Nigeria, trapping 25 aid workers, security and humanitarian sources said.

Scores of Islamic State West Africa Province (ISWAP) fighters invaded the town of Dikwa in restive Borno state, dislodging troops from the military base and torching the humanitarian hub, a military source told AFP on Monday. "We have 25 staff sheltering in the bunker which is under siege by the militants... but so far no staff has been affected," a humanitarian source said, speaking on condition of anonymity.

Military reinforcements, including fighter jets and a helicopter gunship, had been deployed to help repel the attackers, the military source said.

A spokesman for UN chief Antonio Guterres confirmed only that there was a "security incident", but gave no further details.