Drone incidents have been making headlines across Europe for over a week now.

During the night into September 10, an unprecedented wave of Russian drones entered Polish airspace. Up to 19 unmanned aerial vehicles were identified, a handful of which were shot down.

Just days later, Russian drones crossed into the territory of Romania, another NATO member.

On Monday, Polish authorities took down a drone that was flying over government buildings in Warsaw and reportedly detained two suspects, from Belarus and Ukraine.

No one was injured in these incidents, and Russia denies that the incursions were deliberate. Nevertheless, NATO has responded by launching a new mission to safeguard the airspace on its eastern flank.

What is Operation Eastern Sentry?

Dubbed Eastern Sentry, the “multi-domain activity” will involve the strengthening of both ground bases and air defenses and “continue for an undisclosed amount of time,” the defense alliance announced in an official statement on September 12.

The damaged roof of a house is seen against the sky. The beams are visible and hardly anything of the roof itself remains. Wyryki municipality, Poland, September 10, 2025A house in Wyryki was damaged following violations of Polish airspace on September 10Image: Jakub Orzechowski/Agencja Wyborcza.pl/REUTERS

With this new operation, NATO wants to send a clear message both to its eastern member states and to Russia.

The UK and Denmark, among other members, have pledged support for the initiative. Germany has doubled the number of combat aircraft dedicated to air defense in Poland from two to four, and France has deployed Rafale fighter jets. 

‘Sledgehammer on a thumbtack’

While jets and air-to-air missiles have successfully been deployed against drones, they are anything but cost-effective.

“The kind of drone we’re seeing in Ukraine costs between €10,000 and €30,000 [$11,800 to $35,400] a piece. If you’re firing million-dollar missiles at them, you’re going to run out of those very fast,” Chris Kremidas-Courtney, a defense expert at the Brussels-based think tank European Policy Centre (EPC), told DW. “We’re using a sledgehammer on a thumbtack.”

Kremidas-Courtney said European NATO members should instead invest in more efficient modern defense technology that can stop drones at a fraction of the cost, offering the Swedish-built Nimbrix anti-drone missile system as an example. Otherwise, Kremidas-Courtney said, Europe would be stuck with a problematic “cost asymmetry.”

A drone wall?

Poland, Finlandand the Baltic states, which regularly deal with Russian incursions into their airspace, have been asking for an increase in coordinated drone defense for several years.

This concept has often been referred to as a “drone wall” — a term picked up by European Commission President Ursula von der Leyen in her latest State of the Union speech.

A person in helmet and protective military clothing is seen walking through a doorway. The building around the person has been badly damaged in a Russian drone strike, Kharkiv, Ukraine, September 16, 2025A Ukrainian rescuer holds the engine of a Russian drone as he works at the site of a building hit during a Russian drone strike in KharkivImage: Sofiia Gatilova/REUTERS

Ukrainian know-how is set to play a key role in building this figurative wall, with the European Commission announcing a €6 billion ($7.1 billion) joint drone-production project.

“We need to learn from the Ukrainians,” Ian Bond, deputy director of the Brussels-based think tank Centre for European Reform (CER), told DW. “They have a pretty high success rate in bringing down Russian drones, and, if they have the technology to do it, we need to acquire it and copy it.”

NATO to Putin: ‘We will respond’

One of the key challenges for NATO will be to implement new drone defense technology at scale, Admiral Rob Bauer, former chair of NATO’s Military Committee, told DW.

In addition to investing in new hardware, Bauer said, Europe needs to adopt a different mentality toward Russia: “We need to inform our public, and people need to accept there is a threat.”

For its part, the Kremlin has kept repeating the line that it considers NATO to be at war with Russia.

Though NATO denies that this is the case, Bauer said the alliance was in “a gray zone between peace and war” and on high alert. “This is a very important message to Mr. Putin,” Bauer said, “NATO will respond, whatever happens.”

A man in uniform, Former Chair of the NATO Military Committee Admiral Rob Bauer, speaks during an interview in Tallinn, Estonia. September 16, 2022. There is a NATO flag on the table in front of him and a NATO sign behind him‘Message to Mr. Putin: NATO will respond, whatever happens,’ Admiral Bauer told DWImage: Janis Laizans/REUTERS

Bauer said allied defenses proved that they worked when they shot down the drones over Poland shot down the drones over Poland. “I think we passed the test,” he said, “but we have to become better in addressing these new threats.”

Can NATO stop future drone incursions?

Bond, of the CER, is skeptical about the alliance’s current drone defense capabilities. “The impression is that NATO was not prepared for shooting down drones,” he said, “and it needs to step up its game considerably.”

Bond said NATO needed to show more resolve and take down Russian drones whenever it can be safely done — even if they are flying over western Ukraine.

NATO member states have so far refrained from doing so in several cases.

In July, Lithuania reported that two Russian drones had crossed into its airspace but it did not shoot them down. In a statement cited in Lithuanian media, the military reported it would only take such measures in extreme circumstances. Following the incident, Lithuania asked NATO for increased air defenses. 

A Romanian Air Force F16 fighter jet is seen in flightRomania’s Defense Ministry said air force pilots who recently spotted a Russian drone in Romanian airspace ‘assessed the collateral risks and decided not to open fire.’ Pictured here: a Romanian Air Force F16 fighter jet in flight in 2023Image: Gianluca Vannicelli/IPA/picture alliance

Most recently, Romania did not take active measures against a Russian drone in its airspace, which then changed course and headed toward Ukraine. According to Romania’s Defense Ministry, air force pilots who spotted the drone “assessed the collateral risks and decided not to open fire.”

Bond said Russia might read such inaction as an encouraging sign, and drones like these could well go on to strike targets in Ukraine.

Civilian protection measures needed

While intercepting drones is key to defending NATO’s airspace, experts say governments should consider measures such as air raid warning apps and increased shelter capacity.

“It would be a terrifying new step, but I don’t think it’s an excessive step,” defense analyst Bond said.

He said he believed that Russia will continue to test Ukraine’s allies unless they significantly ramp up their own defenses and their support for the country.

Kremidas-Courtney shares this assessment: “We should assume Russia is going to try this every couple of weeks, until we make them pay a price that makes them decide not to.”

NATO hopes that Operation Eastern Sentry will do just that. 

DW’s Teri Schultz contributed reporting.

Edited by: Aingeal Flanagan