WARSAW, Poland (AP) — Polish Prime Minister Donald Tusk accused Russia on Wednesday of planning acts of sabotage worldwide that included “acts of air terror” against airlines.

Tusk spoke at a news conference in Warsaw alongside Ukrainian President Volodymr Zelenskyy.

“I will not go into details, I can only confirm the validity of fears that Russia was planning acts of air terror, not only against Poland, but against airlines around the world,” Tusk said.

The Kremlin has dismissed previous Western claims that Russia sponsored acts of sabotage and attacks in Europe.

Western security officials suspect Russian intelligence was behind a plot to put incendiary devices in packages on cargo planes headed to North America, including one that caught fire at a courier hub in Germany and another that ignited in a warehouse in England last year.

The pro-European Union government in Warsaw says that Russia is pursuing acts of hybrid war against Poland and other Western countries in retaliation for their support for Poland’s neighbor Ukraine in its struggle against Russia's full-scale invasion.

The government has accused Russia, and its ally Belarus, of fomenting a migration crisis on the EU's eastern border with Belarus in order to create chaos and division in the EU.

Last year, Poland's foreign minister ordered the closure of one of three Russian consulates in the country in response to acts of sabotage, including arson attacks that he said were sponsored by Moscow.