Let's roleplay. If you were: A Senior Russian Military planner

I would begin financing training and arming terrorists as clandestinely as possible, even from the terrorists.

For example money and weapons for the US "patriots" who see their government as the enemy - give them guns and money and spread as much right-wing propaganda as they can take. Stir them up and hope that they become a large enough threat inside US borders that the US is too busy dealing with them to look elsewhere.

That's the tactics the US used when it created fundamentalist Muslim terroism, and it worked quite well. Too well some might say.