The captain of an oil tanker believed to be part of Russia's shadow fleet of vessels used to evade sanctions has been charged by French authorities.

The Chinese national was handed one count of refusing to follow instructions from the French navy and told to attend a court hearing in the northern coastal city of Brest next February.

The Boracay left Russia last month and was off the coast of Denmark when unidentified drones forced the temporary closure of several airports last week.

The tanker was boarded by French soldiers earlier this week because it was on a list of vessels subject to EU sanctions for carrying Russian oil exports. Russian President Vladimir Putin called France's actions piracy.

The Kremlin had previously denied any knowledge of the vessel.

The Boracay is currently registered in Benin, but has changed name and flag several times in recent years as part of alleged efforts to evade sanctions brought in response to Russia's full-scale invasion of Ukraine.

The French prosecutor's office stated that the captain could not provide a coherent answer about the flag the ship was carrying.

He and the second captain, also a Chinese national, had been detained since Tuesday while French authorities investigated their actions under suspicion of two offenses: refusing to comply with naval orders and failing to justify the nationality of the ship's flag. The second captain was released without charges after being questioned.

The Boracay is currently anchored near the port of Saint-Nazaire, down the coast from Brest.

Under international maritime law, naval forces can stop a merchant vessel at sea if they have reasonable suspicion that the vessel is without a nationality.

Many Western countries have imposed sanctions on Russian energy, limiting imports and capping the price of its oil in response to the ongoing conflict in Ukraine.

To evade these sanctions, Moscow has allegedly constructed a shadow fleet of tankers whose ownership and movements are obscured.

Russia is believed to have several hundred tankers registered in other countries, used to facilitate the export of its oil. French President Emmanuel Macron asserted that Russia's shadow fleet contains between 600 and 1,000 ships.

The Boracay faced detention by Estonian authorities earlier this year for sailing without a valid country flag.

It had set off from the Russian port of Primorsk on September 20 and sailed through the Baltic Sea, past Denmark, and into the North Sea before proceeding through the English Channel.

It was scheduled to arrive in Vadinar in north-western India on October 20, as per data from the Marine Traffic tracking website.

The matter of whether the tanker was involved in last week's drone intrusion into Danish airspace remains unsettled.

Macron refrained from commenting on the issue while attending a summit on EU security in Copenhagen this past week.

This summit arose in response to recent incursions across Denmark and other European nations.

The drones appeared over various Danish airports and military bases; however, Danish authorities noted no evidence of Russian involvement.

Poland, Estonia, and Romania have reported similar airspace violations from drones or Russian fighter jets. Moscow denies penetrating Estonian airspace and claims any incursions in other instances were mere accidents.