WASHINGTON -- President Barack Obama says the U.S. has deployed 80 military personnel to Chad to help located more than 200 girls kidnapped in Nigeria.

Obama has sent a letter to House Speaker John Boehner and to the Senate notifying lawmakers about the steps underway to assist in the return of the abducted girls.

Obama says the service members will help with intelligence, surveillance and reconnaissance aircraft for missions over northern Nigeria. He says the force will stay in Chad until its support is no longer necessary. Chad shares a portion of its western border with northeastern Nigeria.

The girls were kidnapped last month by an Islamic extremist group known as Boko Haram.