The U.S. military announced on Thursday it will expand wartime training in Germany of Ukrainian military personnel fighting Russia’s invasion with a focus on joint maneuver and combined arms operations.

Pentagon spokesman Brigadier General Patrick Ryder said the training of about 500 Ukrainians a month will start in January, building on more than 15,000 Ukrainian forces trained by the United States and its allies since April.

The new training push will be on top of efforts to teach Ukrainians to operate billions of dollars worth of specialized Western military equipment that the United States and its NATO allies have provided since Russia’s invasion began on Feb. 24.

“Combined arms maneuver training is a logical next step in our ongoing training efforts,” Ryder said, referring to training on how to attack an enemy with multiple capabilities at once.