KANO, NIGERIA - Boko Haram jihadists have raided at least three military posts and overpowered troops in the latest attacks in northeast Nigeria, sources said Wednesday.



Fighters from the IS-affiliated Islamic State West Africa Province (ISWAP) overran the posts in Borno state on Tuesday, military and militia sources told AFP.



The Boko Haram faction has in recent months intensified attacks on military targets in Borno and Yobe states, raiding bases and killing dozens of troops.



"They first dislodged soldiers at a checkpoint in Kimba in Biu ... and then took over another post at Sabon Gari, five kilometers [three miles] away," one military officer said of the latest attacks.



The jihadists launched another attack on a base in nearby Wajirko, according to a militiaman in the area.



On Monday, the jihadists had overwhelmed troops in Buni Gari village in neighboring Yobe state, leading to "some losses," an army officer said.



"Troops were outgunned and forced to retreat after heavy fighting with the terrorists," the military source said.



Reprisals

ISWAP gunmen apparently attacked the village in reprisals over the killing of fellow jihadists in the village last month.



Residents alerted soldiers in a nearby military base as they arrived in trucks.



During an attempt by jihadist fighters to seize another base on Wednesday in Damasak, the army said it lost a helicopter.



Details were scant, but if the aircraft was shot down by the insurgents, it would suggest that they now possess more sophisticated weapons than they have used in the last four years of fighting.



ISWAP has claimed responsibility for the attacks, saying it killed 14 soldiers and took another hostage, according to SITE intelligence, which monitors jihadist activities.



Last week, the group took control of the strategic town of Baga, on the shores of Lake Chad.



Borno and Yobe, along with nearby Adamawa state, have borne the brunt of nine years of jihadist violence that has claimed 27,000 lives and forced 1.8 million people to flee their homes.