The US Coast Guard and Customs and Border Protection (CBP) has detained for inspection a tanker loaded with fuel oil and vacuum gasoil traveling to the state of Louisiana from Russia, the Wall Street Journal reported citing people familiar with the matter.

The vessel, called the Daytona, is owned by the Greek company TMS Tankers Ltd and was chartered by the Swiss-based commodities trader Vitol. Vacuum gasoil is refined into diesel and gasoline, while fuel oil is typically used for heating.

The Daytona was supposed to dock in New Orleans on Sunday with a cargo it picked up in early June from Russia’s Taman Peninsula. The Black Sea port on the other side of the Kerch Strait from Crimea is a terminus for a pipeline from Kazakhstan, among other things.

A Coast Guard official confirmed to the WSJ that the Daytona is undergoing checks by the CBP. TMS Tankers had no comment on the situation, while Vitol told the Journal that they operate “in full compliance with all relevant laws and regulations, including sanctions.”

The US banned all imports of Russian oil, coal and liquid natural gas in March, citing the conflict in Ukraine. The embargo does not apply to products that transit through Russia – including those from Kazakhstan, whose fuel oil and vacuum gasoil exports account for about 25% of the Taman terminal’s business.

According to the Journal, however, the commodity tracking platform Kpler indicates that the Daytona’s cargo is Russian in origin.

At a meeting in Germany on Tuesday, the G7 countries announced they were considering an embargo on all Russian oil shipments around the world, unless Moscow agrees to sell it at a Western-imposed price cap. The proposal comes as energy costs have risen across the globe in response to the anti-Russian sanctions by the US and its allies.