The incident comes as Polish prosecutors revealed that a Russian Gerbera 2 drone found in the Baltic Sea last week had been carrying a high-explosive fragmentation warhead. Polish Prime Minister Donald Tusk warned Sept. 17 that Russia could launch drone or missile strikes against countries that support Ukraine, and try to pass them off as accidents.

European officials have accused Moscow multiple times this year of using sabotage, cyberattacks, espionage and drone operations to pressure Kyiv’s backers as Russia continues its grinding full-scale war on its neighbor.

In August, Germany blamed Russia for an attempted explosive-drone attack at Leipzig/Halle Airport, while earlier this month Danish Prime Minister Mette Frederiksen accused a Russian frigate of firing two flares at a Danish military helicopter. She called the incident an attempt to test NATO and said it was part of Russia’s increasingly aggressive strategy of hybrid warfare.

Russian President Vladimir Putin has said Moscow doesn’t plan to attack NATO countries, but Foreign Minister Sergey Lavrov has warned that any European attack on Russia would trigger a different — and “very short” — war.

Tusk’s office and the Russian Embassy in Warsaw did not immediately respond to POLITICO’s request for comment.