Ukrainian troops are set to begin training on the Patriot missile system in the United States as soon as next week, two U.S. officials familiar with the matter tell CNN.

According to CNN, the training program will take place at Fort Sill in Oklahoma, where the US conducts its own training on operating and maintaining the advanced air defense system.

Fort Sill is one of the Army’s four basic training locations and home to the service’s field artillery school, which has been training service members for more than a century.

The training for the Ukrainians on the complex system is expected to take “several months,” said Laura Cooper, the deputy assistant secretary of defense for Russia, Ukraine and Eurasia.

“I’m not going to be able to give you a specific timeframe for the completion of the training,” Cooper said Friday.