Tusk warns Russia could stage ‘accidental’ strikes on NATO countries supporting Ukraine

Tusk told parliament that intelligence about such potential attacks, including against Poland, had become "very consistent and unfortunately convincing."

"There is a real risk that drones or other types of missiles could enter the territory of one or several countries on the eastern flank, even cause damage, while the official narrative will be that it was an accident," Tusk said.

According to the Polish prime minister, such incidents could be intended to undermine NATO countries' willingness to respond to aggression against a member state and demonstrate that the alliance's Article 5 collective defense guarantee is "only theoretical, not practical."

Tusk described the scenario as the most likely for the coming months, while stressing that it was not the only possible one.

He also said Russia could target road and rail border crossings in Ukraine and potentially cause incidents on the Polish or Moldovan side of the border, disrupting routes used to deliver aid to Ukraine.

Tusk said recent Russian attacks near Poland's border were of particular concern and pointed to jet-powered drones as a new element of the threat.

On Sept. 13, a Russian strike damaged a gas station near the Yahodyn-Dorohusk border crossing and a locomotive nearby. On Sept. 17, a Russian drone crashed or was shot down about four kilometers (2.5 miles) from the Polish-Ukrainian border.

Poland is reinforcing infrastructure near its border with Ukraine in response to the threat. Tusk said mobile shelters would be deployed near border crossings, while air defense capabilities had been established at six crossings, along with an additional command post and radar position.

Earlier, Polish Defense Minister Wladyslaw Kosiniak-Kamysz said Poland was stepping up protection of its airspace following recent Russian "provocations and acts of aggression," including by increasing Air Force activity involving F-16 fighter jets and helicopters.