Against the backdrop of the continuing Russia-Ukraine conflict, NATO's demonstration of military power is dangerous, said a Croatian professor on Wednesday.

Hrvoje Klasic, a history professor at the University of Zagreb in Croatia, told Xinhua News Agency that Air Defender 2023, the largest air deployment exercise in NATO's history, is "a show of force at a time when the situation in Ukraine is deteriorating", and a show of force is "never good because it is always a threat to peace".

NATO should be careful because its activities are straining relations in the world, Klasic said.

Air Defender 2023 began on Monday. About 10,000 soldiers and 250 aircraft, including 70 from Germany and more than 100 from the United States, are participating in the military drill that will last until June 23.

NATO must not become the extended arm of the US, and its members should react "measuredly "to the activities being carried out, Klasic said, adding that "this applies especially to Germany", host of the military exercise.

Weapons will not solve the conflict in Ukraine. Instead, the parties involved should sit down and talk. "At this time, it would be better to find a diplomatic solution, and not to expand the conflict," he said.

About 300 people protested against the exercise in northern Germany on Saturday, saying it "underscores the rejection of negotiations with Russia and further escalates an already threatening situation".