"We warned the Kurds that the Americans will ditch them," said Russia's ambassador to the European Union, Vladimir Chizhov.
Turkey has repeatedly called on the U.S. to stop backing the YPG, which it considers to be terrorists.
The campaign of President Donald Trump released a letter from 235 retired senior officers backing his re-election.
The news comes four years after the Air Force laid out initial plans for what its future fighter jets might look like.
The recent exercises were one of many the Air Force is conducting to test its Advanced Battle Management System.
A veteran of the Marine Corps and Army National Guard, he went through boot camp more than four decades ago.
Cmdr. Robert Arias is at least the third Navy commander removed from his job in recent weeks.