China, South Korea and Japan sharply cut their oil imports from Iran in February following intense US efforts to persuade Asian buyers to comply with Washington sanctions on Iran’s central bank.

Asian countries are collectively the biggest buyer of Iranian crude oil, accounting for about 65 per cent of sales, but their responses to the US sanctions campaign have been mixed. China and India have both resisted US and European Union measures against Iran, whereas Japan and Korea have broadly committed themselves to follow the US lead.

Pressure on China, South Korea and India to further reduce their Iranian oil imports intensified this week when Hillary Clinton, US secretary of state, announced that Japan and 10 European countries had qualified for exemptions from US penalties on institutions that deal with Iran’s central bank. The 11 countries had “significantly reduced” the volume of crude they bought from Iran, Mrs Clinton said.