In an unprecedented attack, Ukrainian aerial drones struck a Russian shadow fleet tanker in neutral waters of the Mediterranean Sea, an official at Ukraine’s Security Service (SBU) told POLITICO on Friday.

The SBU official said the drones hit the tanker Qendil more than 2,000 kilometers from Ukraine, causing critical damage. The vessel was empty at the time of the strike, the official added. The official stressed the attack did not pose any threat to the environment in the region.

According to the Marine Traffic website, the Oman-flagged tanker Qendil is currently in the eastern Mediterranean near Crete and en route to the Russian port of Ust Luga.

“The Russian Federation used this tanker to circumvent sanctions and earn money that went to the war against Ukraine; therefore, from the point of view of international law and the laws and customs of war, this is an absolutely legitimate target for the SBU,” the official said. “The attack in international waters demonstrates that Ukraine will pursue Russian assets wherever they operate and will not allow vessels supporting Moscow’s war effort to act with impunity.”

The strike was announced while Vladimir Putin was holding his annual end-of-year press conference.

Asked about prospects for peace in Ukraine, Putin said he would “love to live in peace next year” — provided a long list of “root causes” of the conflict are addressed, referring to Moscow’s narrative that Ukraine’s NATO membership aspirations must be stopped and that Nazis are allegedly running the government in Kyiv and need to be kicked out.

Veronika Melkozerova contributed to this report.