WARSAW — Polish authorities have closed Warsaw International Airport and Polish and NATO aircraft have been scrambled as reports have surfaced of Russian drones over the country.

The Polish military’s Operational Command said in a statement that “ground-based air defense and radar reconnaissance systems have reached the highest level of alert” after Russia launched massive airstrikes on Ukrainian territory.

“To ensure the security of Polish airspace, the Operational Commander of the Polish Armed Forces has activated all necessary procedures,” the statement said, adding that the Polish military is “fully prepared for immediate response.”

A Notice to Airmen (NOTAM) posted on the US Federal Aviation Administration’s website said Warsaw Chopin Airport was unavailable “due to unplanned military activity related to ensuring state security.”

Earlier, the Ukrainian Air Force said on the Telegram messaging app that drones were heading west and threatening the city of Zamosc in Poland, but the statement has since been deleted, Reuters reported.

It was not immediately clear how many drones were in Poland’s airspace.

Ukrainian media reported that at least one drone was heading towards the western Polish city of Rzeszow.

Rzeszów–Jasionka Airport has been a logistics hub for NATO aid to Ukraine, though the United States pulled its forces from the base earlier this year.

The airport in Lublin, Poland, southeast of Warsaw, was also unavailable due to military activity, a NOTAM said.

Poland earlier announced it was closing its eastern border with Russian ally Belarus as it Belarus prepares for military exercises beginning Friday. — CNN