Exercises includes night-time helicopter assault and the dropping of US paratroopers to build a temporary bridge over Poland’s Vistula river.

A large-scale military training exercise involving more than 20 NATO and partner countries has kicked off in Poland, part of efforts to reassure east European nations rattled by Russia’s actions in nearby Ukraine.

For more than 10 days, 30,000 troops backed by large numbers of vehicles, aircraft and ships will be deployed in one of the biggest exercises on NATO’s eastern flank since the end of the Cold War, a move likely to put further strain on the already-tense relations between the Kremlin and the West.

NATO says exercises such as Anakonda-16, Exercise Saber Strike 16, and plans for the deployment of more troops to the region are a defensive response to Russia’s annexation of Ukraine’s Crimea region and its support for separatists in eastern Ukraine.