China's state-owned oil companies and big private refiners are buying up crude from the Middle East and elsewhere, speeding up preparations for potential fuel supply disruptions as tougher sanctions on Russia and Iran threaten to limit crude supplies in the short term, Bloomberg news agency wrote.

Companies such as Cnooc, Shandong Yulong Petrochemical and Jiangsu Eastern Shenghong are sending out urgent requests to buy crude for quick delivery, traders said Tuesday, adding that various crude grades from the Middle East, Africa and the Americas are being considered.

They said February cargoes are in particular demand. The decision by some of China's biggest oil buyers stems from concerns that smaller private refiners, already under pressure, may be forced to cut operating rates and reduce fuel production if they no longer have access to discounted Russian and Iranian crude, the agency notes.

The latest round of sanctions imposed by Washington affects more than 180 tankers and some of Russia's largest oil producers, Bloomberg emphasizes.

As the media outlet notes, these measures have affected the Asian oil market: buyers, shippers and port operators are trying to cope with the consequences.