Niger and the United States have reached an agreement on the withdrawal of American troops from the West African country, a process that has already begun and will be finished by Sept. 15, they said in a joint statement.

Niger’s ruling junta last month told the U.S. to withdraw its nearly 1,000 military personnel from the country.

A senior U.S. military official, speaking on condition of anonymity, said that about 100 U.S. troops had already been moved out of the country.