The October 2024 floods claimed 235 lives nationwide and caused widespread damage. Most of the deaths were in the eastern Valencia region, where popular fury targeted officials in the aftermath.

The "pro-Kremlin propaganda and disinformation ecosystem" exploited the floods with opportunism to fuel public distrust in state institutions, the annual report said.

It described how activists spread messages claiming that Socialist Prime Minister Pedro Sanchez's government was diverting public funds to support Ukraine after Russia's invasion at the expense of "Spain's real need for aid".

Pro-Russian groups also intensified disinformation campaigns ahead of the European Parliament elections in June 2024 in an effort to undermine trust in the electoral system, the report said.

Russian intelligence services and allied organisations seek to "increase pre-existing social or political divisions in the target country, undermine its cohesion and, ideally, foster a rapprochement with Russian theses," the report added.

The European Union warned in March that Russia and China were using "massive digital arsenals" to interfere in Western democracies, while their messaging around the Ukraine war had become increasingly aligned.

The EU has grown more concerned about Russian interference as part of what it sees as a broader hybrid campaign from Moscow that includes sabotage attacks to weaken the West.

Brussels imposed sanctions on Russian intelligence operatives in December over the alleged malign activities.

False claims spread rapidly online following Spain's floods, with some posts -- often shared on platforms linked to Russia -- alleging the government was hiding the true number of victims.

Other unfounded reports falsely blamed dam failures for the flooding and warned, without evidence, of contaminated drinking water in the Valencia region.

Against this backdrop, furious locals hurled mud and insults at Sanchez, King Felipe VI and Queen Letizia in November 2024 when they visited one of the worst-hit towns in a startling show of anger.