The incursion into Poland deepened longstanding fears that the three-year war between Poland’s neighbors could precipitate a wider conflict.

Europe has "nowhere near enough volume to defend itself in the event of a major and protracted war," Matthew Savill told Newsweek.

Denmark, France and Germany have joined a new mission to bolster the military alliance's eastern flank after Russian drones flew into Poland on Wednesday.

US president said he is ready to impose further sanctions on Russia, but only if all NATO countries stop buying Russian oil, a huge source of income for Putin.

Alarms bells sounded this week in Europe after NATO jets scrambled to intercept an unprecedented Russian drone incursion in Poland. Now there is fresh unease on NATO’s eastern flank, as Russia and Belarus kick off major military drills to test the readiness of their armed forces.

Jen Psaki explains that after NATO members in Europe responded with alarm to an incursion of Russian drones into Poland, risking a drastic escalation, Donald Trump seemed more inclined to make excuses for Vladimir Putin than to stand with allies in discouraging Russian belligerence.

Amid rising tensions between NATO and Russia, Moscow and Belarus are holding military exercises starting on Friday that include "planning the use of nuclear weapons" and testing ballistic missiles, the state-run Tass news agency reported.