DAKAR, Senegal (AP) — In an open letter Thursday to U.N. Secretary-General Ban Ki-moon, the president of the African Union urged the U.N. to take immediate military action in northern Mali, which was seized by al-Qaida-linked rebels earlier this year.

Yayi Boni, the president of Benin who is also head of the African Union, said any reticence on the part of the U.N. will be interpreted as a sign of weakness by the terrorists now operating in Mali. The AU is waiting for the U.N. to sign off on a military plan to take back the occupied territory, and the Security Council is expected to discuss it in coming days.