Ukrainian President Volodymyr Zelensky has accused Russia of converting oil tankers into drone launch and control centres targeting European countries, calling for tougher sanctions on Moscow's energy trade, reports Ukraine's Kyiv Post.

In a video address, Mr Zelensky said intelligence reports show Russian tankers are being used to deploy UAVs against Western targets. He urged Europe to bar Russian vessels from regional waters, especially the shadow fleet.

He stressed the need for sanctions to hit Russia's energy infrastructure, describing the tanker fleet as both an economic and security threat beyond Ukraine.

He also called on Washington to take stronger action, saying Kyiv expects "strong steps from the United States of America" to help end the war. He said he discussed options with President Trump.

The remarks follow a rise in drone sightings across Europe. Unidentified UAVs have been reported near military sites in Denmark, Sweden, Finland, Poland and other countries, prompting investigations.

Danish police confirmed sightings of drones over Karup military base, which houses helicopters, airspace surveillance and flight school operations. Airports in Denmark and Norway were temporarily closed due to drone activity.

Similar incidents have occurred in Poland, Romania and Estonia, where Russian fighter-bombers violated airspace. Danish Prime Minister Mette Frederiksen said the country had suffered "hybrid attacks" in recent days.

Danish Defence Minister Troels Lund Poulsen said the drone flights appeared to be "the work of a professional actor". Frederiksen identified Russia as the main threat to European security.