Russian shadow fleet drones spied on nuclear sites and airports across Europe, IISS report reveals

Scale of the campaign

The International Institute for Strategic Studies (IISS) catalogued 144 suspicious drone sightings across 12 NATO member states and Ireland over an 18-month period ending in February 2026. Nearly half (48%) occurred above military installations, including sites linked to nuclear weapons, while 18% forced temporary closures at civilian airports in Germany, Spain, and Denmark. Another quarter targeted critical infrastructure: ports, energy facilities, and industrial plants. Germany recorded the highest tally at 58 incidents, among them six over the US Ramstein airbase and several over Bundeswehr sites. Belgium followed with 25, Denmark 16, and the Netherlands 9.

Germany58

Belgium25

Denmark16

Netherlands9

Other countries36

Germany

58

Belgium

25

Denmark

16

Netherlands

9

Other countries

36

Data from the article text

The peak came in late 2025, when drone sightings forced brief shutdowns at several European airports. Danish Prime Minister Mette Frederiksen called the disruption

“the most serious attack against Danish critical infrastructure to date.”

Timeline of key incursions

The campaign unfolded in distinct phases, with the IISS linking specific episodes to vessels of the Russian shadow fleet.

At the end of November 2024, low-flying unidentified drones were spotted over RAF Lakenheath and RAF Fairford in the UK, as well as two other US Air Force bases in England. Lakenheath was preparing to host American nuclear weapons at the time. Researchers believe the drones were controlled from the tanker Seasons 1 in the North Sea off Essex, or from the cargo ship Hav Dolphin en route to Hull.

In May 2025 a drone sighting above a submarine base in northern Germany was also traced to Hav Dolphin. The most concentrated activity came in November and December 2025, when drones flew over the Kleine Brogel airbase in Belgium and the Volkel airbase in the Netherlands, both storage sites for US B61-12 nuclear bombs. In December 2025, five drones were detected over the Île Longue submarine base in France, the heart of the French sea-launched nuclear deterrent. Three ships of the Kremlin's shadow fleet were between 100 and 200 kilometres from shore at the time, while Hav Dolphin was 350 kilometres away near the Isle of Wight.

Shadow fleet connection

The IISS report concludes that Russia used tankers, coastal freighters, and smaller support vessels from its clandestine shipping network to launch drones. Some ships served as launch platforms while others relayed signals to extend the drones' range. Drones flew low and were difficult for conventional radar to track, allowing them to operate with what the report calls "substantial impunity". Not a single drone was captured or shot down by the targeted nations.

European response and strategic failure

Western governments have been reluctant to publicly accuse Moscow. Only Sweden has directly blamed Russia, after a military drone flew toward a French aircraft carrier from a Russian spy ship. John Stringer, NATO's Deputy Supreme Allied Commander Europe, told the Associated Press that

“it is up to each member of the alliance to decide how to respond to such threats, and many countries are taking them increasingly seriously.”

The IISS characterises the episode as a "strategic failure" for Europe, exposing air defences still geared toward conventional threats rather than low-observable unmanned systems.

Russian President Vladimir Putin stated in May 2026 that

“Russia is not waging a sabotage campaign against Europe.”

The Danish police closed their own investigation into the drone sightings in June 2026, saying they could not confirm the presence of drones, a finding at odds with a separate report by the Danish armed forces, which said experienced troops identified and opened fire on a drone over a training base.

Renewed alert over Ireland

The fallout continued as recently as 1 July 2026. Irish Air Corps aircraft were scrambled to escort the plane of Ukrainian President Volodymyr Zelensky into Dublin, one day before the IISS report was released. During a previous visit in December 2025, four or five large military-style drones breached the no-fly zone on his flight path. Irish navy vessels tracked the drones but could not engage for fear of hitting civilians. The incident underscored that the threat documented by the 144 sightings had not abated.

The IISS researcher Charlie Edwards noted that

“every government I have discussed this with has said it will welcome the publication of the report.”