Poland has deployed fighter aircraft after Russian drones were detected operating over Ukrainian territory close to its eastern border, Polish Prime Minister Donald Tusk confirms.

"Due to the threat posed by Russian drones operating over Ukraine near the border with Poland, preventive operations of aviation – Polish and allied – have begun in our airspace. Ground-based air defence systems have reached the highest state of readiness,’"Tusk wrote on X.

The move underlines growing concern in Warsaw over the spillover risk from Russia’s war in Ukraine.

In recent months, several incidents have seen debris from Russian missiles and drones fall inside Polish territory, prompting demands for stronger NATO coordination and deterrence measures.

US Secretary of State Marco Rubio on Saturday called the incursion of 17 Russian-made drones into Polish airspace during an attack on Ukraine earlier this week an "unfortunate and dangerous development."

"The question is whether the drones were targeted to go into Poland specifically. If that's the case, if the evidence leads us there, then obviously it will be... highly escalatory," Rubio told reporters in Washington.

This is a developing story with updates to follow.