Russia used shadow fleet drones to spy on European nuclear sites for 18 months, IISS report reveals

The IISS investigation

An analysis by the London-based International Institute of Strategic Studies (IISS) published on Thursday concludes that Russia conducted a coordinated drone surveillance campaign over 13 European NATO countries between August 2024 and February 2026. The think-tank examined 144 separate incidents, finding that not a single drone was intercepted or shot down by Western forces. The report describes the operation as a series of tactical successes for Moscow and a strategic failure for allied air defence, exploiting gaps in how European militaries are equipped and authorised to deal with low-altitude drone threats.

The unmanned aerial vehicle (UAV) campaign operated with substantial impunity across European airspace — representing both a series of tactical successes for the Kremlin and a strategic failure of allied air defence.

Nuclear sites and military bases targeted

The unarmed drones repeatedly appeared over some of NATO's most sensitive installations. In the United Kingdom, they were spotted at RAF Lakenheath and RAF Fairford in November 2024. RAF Lakenheath began hosting US nuclear weapons in July 2025. France's Île Longue nuclear submarine base was overflown by five drones in December 2025. Belgian and Dutch bases housing American B61 nuclear bombs, Kleine Brogel and Volkel, were also targeted in November and December 2025. A drone was neutralised near the French aircraft carrier Charles de Gaulle in February 2026, an incident that Swedish military authorities linked to a Russian spy ship.

Launch platform: The shadow fleet

The IISS researchers traced the flights to commercial vessels linked to Russia's so-called shadow fleet, tankers and cargo ships that operate with transponders off to evade sanctions. Ships identified include the tanker Seasons 1 and the cargo vessel Hav Dolphin, both tracked in the North Sea during drone sightings at UK bases. Hav Dolphin was later suspected of launching drones near a German submarine base in May 2025. In September 2025, French forces boarded the tanker Boracay and detained two Russian nationals working for the private military company Moran Security Group, evidence, the report says, of the shadow fleet's militarisation. The spy ship Zhigulevsk was confirmed as a launch platform for the drone near the Charles de Gaulle.

Civilian disruption and weak air defence

The campaign also spilled over into civilian life. Airports in Copenhagen, Munich, Oslo, Vilnius and other cities were repeatedly closed at its peak in late 2025, disrupting flights. According to the report, 48% of all drone sightings were over military installations, 18% over civil airports and 26% over critical infrastructure such as ports and energy sites.

European governments have so far refrained from publicly blaming Russia, though they acknowledge the problem in private. NATO Deputy Supreme Allied Commander Europe, Air Marshal John Stringer, told the Associated Press that it remains up to each member state to decide how to respond and that many are now taking the threat more seriously. The IISS criticises the fragmented response and calls for a collective upgrade of air defence capabilities to counter maritime-launched drones.

Moscow's denial and strategic intent

Russia has repeatedly denied involvement. President Vladimir Putin stated in May 2026 that Russia was not conducting a sabotage campaign against Europe. The IISS assesses that the drone operations aimed to stay below the threshold that would trigger a collective NATO response, combining nuclear site surveillance, reconnaissance of military logistics, and intimidation. The think-tank argues that the campaign successfully exploited legal and procedural gaps in European rules for using force against drones, leaving the continent exposed.