The U.S. military mission in Liberia to fight Ebola is expected to end next month, Fox News has learned. 

A senior U.S. Defense official said an announcement is planned next week. 

USA Today first reported that, as infection rates in the West African region near zero, the U.S. military mission will wind down. 

The number of troops, which was at almost 3,000, reportedly will fall to 1,300 this week and then decline further. 

Troops in West Africa built clinics and offered medical training while on the five-month mission. The outbreak killed thousands in Liberia, but the infection rate has since plummeted.   

Fox News' Jennifer Griffin contributed to this report.