France, May 22 -- In a report published on Friday, the conflict-monitoring organisation ACLED describes an increasingly emboldened maritime system that allows Moscow not only to circumvent sanctions, but to operate in the grey area between commerce, espionage, intimidation and sabotage.

Despite hundreds of sanctions, Russia is still successfully using the fleet to sustain its war economy, exposing vulnerabilities in Europe's critical infrastructure.

According to ACLED, the fleet comprises anywhere between 1,000 and 3,200 vessels. Ukrainian authorities have identified nearly 1,400 ships, while estimates suggest the network now transports up to 80 percent of Russia's seaborne crude exports.

Many of the vessels are ageing tankers hidden b...