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.

Until a coup last year Niger had been a key partner in Washington's fight against insurgents in the Sahel region of Africa, who have killed thousands of people and displaced millions more.

The agreement between Niger's defence ministry and the U.S. Department of Defence, reached after a five-day meeting, guarantees the protection of U.S. troops until their withdrawal and establishes procedures to ease the entry and exit of American personnel during the withdrawal process.

"The Ministry of Defence of Niger and the U.S. Department of Defense recall the common sacrifices of the Nigerien and American forces in the fight against terrorism and welcome the mutual efforts made in building up the Nigerien armed forces," they said in a joint statement.

"The withdrawal of American forces from Niger in no way affects the pursuit of relations between the United States and Niger in the area of development.

"Also, Niger and the United States are committed to an ongoing diplomatic dialogue to define the future of their bilateral relations."

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.

The United States will remove sensitive equipment it has in Niger, but will leave behind other larger pieces like air conditioning units, generators and hangars, a separate U.S. defense official said.

The United States will let Nigerien forces use that equipment left behind, if it meets legal standards, the official said.

The official added that it did not appear that the Nigerien junta wanted to hand over counter-terrorism operations to Russian troops or those from the Wagner private military company.

"I think we tend to believe what they've told us, at least the CNSP, which is they're not looking for any foreign forces in large numbers here," the official said, using an acronym for Niger's ruling military council.

Niger's decision to ask for the removal of U.S. troops came after a meeting in Niamey in mid-March, when senior U.S. officials raised concerns about issues such as the expected arrival of Russian forces and reports of Iran seeking raw materials in the country, including uranium.

Russian military personnel have since entered an air base in Niger that is hosting U.S. troops.