A major U.S.-led military exercise with 18,000 soldiers from 19 countries, primarily members of NATO, has kicked off in the alliance's eastern flank involving Poland and the three Baltic states of Estonia, Latvia, Lithuania.

The U.S. Army Europe said Sunday the Sabre Strike 18 drill is spread around the region until June 15 as "a demonstration of the commitment and solidarity of the Alliance" at the time when Russia's military manoeuvres are increasingly worrying nearby NATO members.

It stressed, however, that Sabre Strike "is not a provocation of Russia."

NATO has deployed some 6,000 troops in the Baltics and Poland.

Lithuania's defence ministry also announced the start of the country's largest-ever national drill, Thunder Storm, with some 9,000 troops.

Non-NATO member Israel will be taking part in Sabre Strike for the first time.

Canada is participating in Sabre Strike 18 and another NATO exercise in Latvia called Summer Shield, the Canadian Department of National Defence said. Canadian soldiers will be participating in the exercises from June 3-15.