U.S. troops ordered out of Niger by the West African country’s ruling junta will complete their withdrawal by the middle of September, the Pentagon and Nigerien defense officials said Sunday.

The timeline was the product of four days of talks between the countries’ defense officials in the capital city of Niamey, according to a joint statement.

Niger’s decision to kick out American forces dealt a blow to U.S. military operations in the Sahel, a vast region south of the Sahara desert where groups linked to al-Qaida and the Islamic State group operate.

The rupture in military cooperation followed last July’s ouster of the country’s democratically elected president by mutinous soldiers. A few months later, the ruling junta asked French forces to leave and turned to the Russian mercenary group Wagner for security assistance.

In October, Washington officially designated the military takeover as a coup, which triggered U.S. laws restricting the military support and aid that it can provide to Niger.

About 1,000 U.S. troops are still in Niger, mostly on an airbase near Agadez, some 920 kilometers (550 miles) away from the capital.

Until recently, Washington considered Niger a key partner and ally in a region swept by coups in recent years, investing millions of dollars in the Agadez base, which has been critical to U.S. counterterrorism operations in the Sahel. The United States also has invested hundreds of millions of dollars in training Niger’s military since it began operations there in 2013.

The Pentagon has said the U.S. will relocate most of the approximately 100 forces it has deployed in neighboring Chad for now. But talks are expected to resume next month about revising an agreement that allows U.S. troops to be based in Chad.