The United States is sending 300 troops to Cameroon to help in the fight against Boko Haram insurgents after the group vowed to attack the West African country for agreeing to help Nigeria defeat it.

NBC, the American broadcast station, reported that President Barack Obama notified John Boehner, Speaker of the U.S. House of Representatives, in a letter which was read on Wednesday.

The deployment, which began on Monday, is reportedly is response to a request by Cameroonian government.

Already, about 90 troops are said to be on their way to Cameroon to conduct “airborne intelligence, surveillance and reconnaissance operations in the region.”