NATO to kick off nuclear drills involving B-52 bombers on Monday

FILE PHOTO: U.S. Air Force B-52 bomber flies during the annual recurring multinational, maritime-focused NATO exercise BALTOPS 2017 near Ventspils, Latvia June 6, 2017. REUTERS/Ints Kalnins

BRUSSELS (Reuters) - NATO said on Friday it would launch its annual nuclear exercise "Steadfast Noon" on Monday, with up to 60 aircraft taking part in training flights over Belgium, the North Sea and Britain to practise the use of U.S. nuclear bombs based in Europe.

The nuclear drills - which do not involve live bombs - are taking place amid heightened tensions after Russia repeatedly threatened nuclear strikes in Ukraine following major military setbacks on the battlefield there.