The White House says about 90 U.S. service members are en route to the African nation of Cameroon to conduct airborne intelligence, surveillance and reconnaissance operations in the region.

President Barack Obama notified House Speaker John Boehner, a Republican, in a letter. The White House released the letter Wednesday.

U.S. personnel began deploying on Monday under an arrangement with the Cameroon government. A total of up to about 300 U.S. service members could be sent.

They will be armed to provide their own protection and security and will stay in Cameroon until they are no longer needed.

Cameroon has been battling Boko Haram militants based in neighboring Nigeria. The group has vowed to retaliate against Cameroon for backing the Nigerian military's mission to defeat Boko Haram.