WARSAW, Poland (AP) — Two U.S. stealth F-22 fighter jets have arrived in Poland to carry out combat air exercises for a day with the Polish air force.

The exercises are part of a broader U.S. policy of assurance to NATO allies in Eastern Europe worried about Russian aggression.

The two F-22 Raptor jets arrived on Monday at Lask Air Base in central Poland. They are part of the first U.S. deployment of the high-tech jets to Europe.

The U.S. Embassy in Warsaw said that four F-22 Raptors arrived last week at the Spangdahlem Air Base in Germany and will remain there until mid-September.