WARSAW, Poland (AP) — Poland said early Wednesday that it and its NATO allies had shot down Russian drones that violated Polish airspace in what it called an “act of aggression” as Russia launched aerial attacks on Ukraine.

Polish Prime Minister Donald Tusk wrote on social media that “Last night the Polish airspace was violated by a huge number of Russian drones. Those drones that posed a direct threat were shot down.”

Poland’s armed forces were on a heightened state of alert overnight Tuesday and early Wednesday because of what they described as “further massive airstrikes against targets located in Ukraine.”

Defense Minister Władysław Kosiniak-Kamysz wrote on X that “more than 10 objects” crossed into Polish air space and those that constituted a risk to Poland’s security were neutralized. He thanked NATO Air Command and The Royal Netherlands Air and Space Force for supporting the action with F-35 fighter jets.

The Polish armed forces said Wednesday morning that a search for possible crash sites is ongoing and urged people not to approach, touch or move any objects they see, warning that they may pose a threat and could contain hazardous material.

Warsaw’s Chopin Airport suspended flights for several hours, citing the closure of airspace due to military operations.

European Union foreign policy chief Kaja Kallas said that early indications suggest the drone incident was intentional.

“Last night in Poland we saw the most serious European airspace violation by Russia since the war began, and indications suggest it was intentional, not accidental,” Kallas said in a statement.

The EU’s top diplomat said that she is in contact with NATO and Poland’s foreign minister and following developments.

“The EU stands in full solidarity with Poland. Russia’s war is escalating, not ending. We must raise the cost to Moscow, strengthen support for Ukraine, and invest in Europe’s defense,” she said.

Poland has complained about Russian objects entering its airspace during attacks on Ukraine before.

In August, Poland’s defense minister said that a flying object that crashed and exploded in a cornfield in eastern Poland was identified as a Russian drone, and called it a provocation by Russia. In March, Poland scrambled jets after a Russian missile briefly passed through Polish air space on its way to a target in western Ukraine, and in 2022, a missile that was likely fired by Ukraine to intercept a Russian attack landed in Poland, killing two people.

Meanwhile, Russian drones injured three people in Ukraine’s western Khmelnytskyi region, its head Serhii Tiurin wrote on Telegram early Wednesday morning. He said a sewing factory was destroyed, a gas station and vehicles were damaged, and windows in several houses were blown out.

One person was killed and one injured in Zhytomyr region overnight, regional administration head Vitalii Bunechko wrote on Telegram, while homes and businesses suffered damage.

In Vinnytsia region, Russian drones damaged “civilian and industrial infrastructure,” according to regional head Natalia Zabolotna. Nearly 30 residential buildings were damaged and one person was injured.

In Cherkasy region, several houses and a power grid were damaged in a Russian attack. In Zolotonosha district, a shock wave destroyed a barn killing two cows, regional head Ihor Taburets wrote on Telegram.

The Russian Defense Ministry said in its morning report on Wednesday that it had destroyed 122 Ukrainian drones over various Russian regions overnight, including over the illegally annexed Crimea and areas of the Black Sea.

Joint military drills involving Russian and Belarusian troops are due to take place in Belarus starting Friday and will last until Sept. 16.

Troops from both countries will simulate repelling an attack, including airstrikes and sabotage, according to official reports of the games, dubbed “Zapad 2025,” or “West 2025.”

The aim is to showcase the close links between Moscow and Minsk, as well as Russian military might, amid its 3½-year-old war in neighboring Ukraine.

The war games have drawn concerns in Kyiv and its Western allies of Latvia, Lithuania and Poland, which border Belarus. When Russian President Vladimir Putin sent troops rolling into Ukraine on Feb. 24, 2022, many of them crossed from Belarus.

Novikov reported from Kyiv, Ukraine. AP writers Lorne Cook in Brussels and Geir Moulson in Berlin contributed to this report.