MOSCOW (AP) — Russia's defense ministry says President Vladimir Putin has announced snap military drills on land and in the Black and Caspian Seas.

The ministry said in a statement Thursday that the drills began at 7:00 a.m. (0400 GMT) Moscow time in Russia's southern, western and central military districts where troops have been put on combat alert.

The drills which will last until the end of the month will involve a variety of troops, from paratroopers to the Northern Fleet.

The drills come a week after Russia for the first time since it began its operation in Syria used an air base in Iran, and after President Putin lashed out at Ukraine for allegedly sending its military intelligence office to carry out acts of sabotage in Russia-annexed Crimea.