Tomasz Siemoniak said the training exercise, centered on the Lask air force base in central Poland, was originally to have been smaller and involved only transport aircraft. He said Poland requested it be beefed up after Russia's intervention in Ukraine's Crimea Peninsula.
Standing at a news briefing alongside the minister, US ambassador to Poland Stephen Mull said: "When we face such a dramatic challenge for our security, we need to reassure our allies that our security guarantees are valid."