LASK, Poland — The U.S. has opened its first permanent military presence on Polish soil, an Air Force detachment to service warplanes, in a move long sought by its NATO ally Poland.

President Barack Obama announced plans to station Air Force personnel at Lask Air Base, near Lodz, during a visit last year after Warsaw pressed for what it sees as a security guarantee in the face of a more assertive Russia.

Starting next year, the 10 resident U.S. staff members will service four annual aircraft rotations, mainly of F-16 fighter jets and C-130 Hercules transport planes. Up to 200 uniformed personnel and civilian contractors will also be temporarily on the base.

“This is a very important and symbolic moment for our relations,” said Polish Defense Minister Tomasz Siemoniak at an opening ceremony Friday. “This is not just rhetoric but a very tangible example.”

The increased presence of U.S. military in Poland is certain to complicate relations with Russia, already concerned about Washington’s plans to station part of a missile shield on the soil of a former Soviet satellite.

Poland, one of the most pro-American countries in Europe, had looked skeptically at Obama’s efforts to “reset” relations with Moscow.

Many Poles were concerned that early on, he appeared indifferent to central Europe and its security concerns. Obama has modified the shield plan, which envisions stationing SM-3 missile interceptors in Poland, but it continues to be opposed by Russia.

“President Obama is absolutely determined to form a [missile shield] base in Redzikowo in 2018,” said U.S. Ambassador Stephen Mull, who took up his post in Warsaw last week.