Government spokesman Sebastian Hille said the incident "once again shows the threat that we face" and how much Germany and other NATO countries "are being tested by Russia".

Defence Minister Boris Pistorius meanwhile told the German parliament the drones were "clearly set on this course" and "did not have to fly this route to reach Ukraine".

"There is absolutely no reason to believe that this was a course correction error or anything of the sort," Pistorius said.

Foreign Minister Johann Wadephul said Russia had "carelessly risked a dangerous escalation" with drones entering Polish airspace "on a significant scale".

He added that "Russia must know that NATO is capable of action and that it will react to defend NATO territory".

Poland was gathering its NATO allies for urgent talks Wednesday after the Russian drones flew into its airspace during an overnight attack on Ukraine.

Prime Minister Donald Tusk denounced the "large-scale provocation", saying Poland had identified 19 violations of its airspace and shot down at least three drones.

Tusk said he had invoked NATO's Article 4 under which a member can call urgent talks when it feels its "territorial integrity, political independence or security" are at risk -- only the eighth time the measure has ever been used.

Pistorius said the drone incursion was an example of "what we have been talking about regularly for at least two years, namely that we are under constant threat from provocations by Russian forces".

These threats could be seen "in the Baltic airspace, in the Baltic Sea... but also in Central Europe through hybrid attacks or through such (drone) flights", he said.

Germany is cooperating with Poland in the form of consultations under Article 4, Pistorius added.

"We support this approach, which we consider to be correct," he said.