Poland scrambled jets on Tuesday after Russia launched a large-scale missile and drone attack on Ukraine overnight.
The Nato country’s Armed Forces’ Operational Command said that a pair of fighter jets and an early warning aircraft had been deployed after detecting long-range Russian missiles striking Ukraine nearby.
Ground-based air defence systems and radar reconnaissance also reached a “maximum state of readiness”, it said.
“These actions are of a preventive nature and are aimed at securing the airspace and its protection, particularly in areas adjacent to the threatened regions,” Poland’s army said in a statement on X.
“The Operational Command of the Armed Forces is monitoring the current situation, and the subordinate forces and resources remain ready for immediate response.”
President Volodymyr Zelensky said four people had been killed in the attacks on 11 regions, with dozens more injured.
The overnight Russian attack consisted of nearly 40 drones launched against Shostka in the Sumy region of Ukraine, he wrote in a post on X on Tuesday. In Slatyne, Kharkiv, he said a drone had struck an electric train.
He added: “In total, there were over 390 strike drones and 34 missiles of various types – ballistic, cruise, and guided air-launched missiles.
“These numbers clearly show that more protection is needed to save lives from Russian strikes. It is important to continue supporting Ukraine.”
It is not the first time that Poland has been forced to ready itself for a possible attack.
There have been several incursions into the country’s airspace, prompting its leader to call for a no-fly zone over its territory in September last year.
Polish fighter jets intercepted a Russian reconnaissance aircraft operating near its airspace over the Baltic Sea in December, according to the country’s army.
Nations on Nato’s eastern flank have remained on high alert for potential airspace incursions after a spate of airspace incursions in recent months including disruptions to airports in Lithuania in December and a violation of Estonian airspace by three Russian military jets for 12 minutes in September. Romania and Denmark have also been affected.
States have accused President Vladimir Putin of conducting “hybrid warfare”, causing disruptions to travel and military systems without a direct attack. The Kremlin has denied the claims.
Nato has not reacted collectively to the intrusions with military intervention so far, although defences were bolstered along the alliance’s eastern flank where the majority of the disruptions have occurred.