While the U.S. has taken part in previous iterations of the military exercise, this year's U.S. footprint was smaller as allied nations are pressed by the Trump administration to put more into European defense.

Tensions rose after a blast damaged the Warsaw-Lublin rail line, which has been used to deliver aid to Ukraine, and a Russian missile attack killed at least 25 people in Ternopil.

A spokesperson for Poland's special services minister accused Russian intelligence Tuesday of orchestrating a railway blast that destroyed a key track on a route used to deliver aid to Ukraine. Jacek Dobrzyński told reporters that "everything indicates" Russian intelligence was behind the sabotage of Polish railways.

Business Insider observed US, Polish, and Romanian forces learning to use the Merops system, which has been combat-proven in Ukraine.

NATO was forced to scramble fighter jets after the Russian forces launched one of the biggest drone and missile attacks on Ukraine. At least 25 people have been killed and 75 injured – with

The drone incursions and the instability on NATO’s eastern flank stem from Russia’s war in Ukraine, now approaching the end of its fourth year. The conflict has become a crucible for drone development, transforming the battlefield into a testing zone for new technology which now has applications elsewhere in Europe.

Exclusive: Russia reacts after a key rail line in Poland was struck by an explosive device, with Moscow blamed.

Professor Michael Clarke has been answering your Ukraine war questions - scroll down for the best of his answers or watch back in the video below.

Poland said on Wednesday it would close the last Russian consulate in its territory and deploy thousands of soldiers to protect infrastructure in response to a railway explosion it blames on Moscow.