France announced Monday it had detained a suspected Russian oil tanker in the Atlantic over the weekend, in the latest move to crack down on Moscow's sanctions-busting "shadow fleet."

The Tagor was detained Sunday morning in international waters with the help of Britain and other partners, said President Emmanuel Macron.

According to French authorities, the tanker was on its way from Murmansk in northwestern Russia when it was seized.

The ship was falsely flying a Cameroonian flag and was heading toward Limbe, a seaside city in the west of the African country, said a spokesperson for the maritime prefecture.

"It is unacceptable for ships to circumvent international sanctions, violate the law of the sea and fund the war that Russia has been waging against Ukraine for more than 4 years," Macron said.