The United States has imposed its biggest sanctions on Russian oil prices.

The move comes after the United States last month imposed sanctions for the first time on the owners of two tankers, the Yasakin Bosphorus and the SCF Primorsky Frontier, for shipping Russian oil at prices above the ceiling. One of the companies that received the notice was Turkey's Beks Shipping, while the others have not been disclosed.

The U.S. request for information is a routine step in sanctions investigations to gather details, such as information on companies that charter certain ships or buy the oil they transport, the sources said. The United States has imposed sanctions on three Dubai-based shipping companies and three oil tankers. The sanctioned UAE companies include KAZAN SHIPPING, PROGRESS SHIPPING and GALLION SHIPPING. The reason is that the price of oil they ship is above the G7 ceiling of $60 a barrel. Meanwhile, the companies are believed to be linked to SOVCOMFLOT, Russia's largest shipping company, and the sanctioned vessels have been transporting Russian oil to India in recent months.

In response, the U.S. Deputy Treasury secretary said the United States is committed to maintaining market stability while cutting the Kremlin's spending to fund its illegal war and steadfastly pursuing those who assist in circumventing price caps.

In December 2022, the European Union, the G7 and Australia imposed a $60 per barrel price cap on Russian crude oil to prevent Russia from using oil revenues to fund its war in Ukraine. The aim of the policy is to prohibit the provision of transportation, financing and related insurance services for Russian oil at prices higher than the price caps set by the G7 and its coalition partners.

However, the price cap is almost "unenforceable" due to the rebound in global oil prices this year and the rise of a "shadow tanker fleet", according to the World Bank's latest commodities market report. The average price of Russian crude oil has breached the ceiling for more than three months in a row, and the official benchmark price of Urals crude oil still averaged over $80 per barrel in August.

In response, U.S. officials say the cap still imposes additional costs on Russia, forcing it to rely more on a "shadow tanker fleet" of aging tankers, as well as longer ranges and non-Western shipping services.

In addition, some of the vessels currently under investigation were involved in transporting Russian oil from the Pacific port of Kozmino, while others loaded Russian oil at the port of Primorsk in the Gulf of Finland, the sources said. In such cases, a US official said that the G7 and the EU would not kill each other in one fell swoop during the implementation process. U.S. service providers will not be subject to sanctions if others in the transportation chain provide false or misleading information about Russian oil prices to U.S. service providers.