(CNN) -- China, South Korea and Japan dramatically 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 buyers of Iranian crude oil, accounting for about 65 per cent of Tehran's sales, but their responses to Washington's sanctions campaign have been mixed. China and India have both resisted the US and EU sanctions on Iran, whereas Japan and Korea have broadly committed to follow the US lead. Pressure on China, South Korea and India to further reduce their imports of Iranian oil intensified this week when Hillary Clinton, US secretary of state, announced that Japan and ten European countries had qualified for exemptions from US penalties on institutions that deal with Iran's central bank. These 11 countries had "significantly reduced" the volume of crude they purchased from Iran, according to Mrs Clinton's statement.
@highlight
Cut of oil imports come after US efforts to persuade Asian buyers to comply with Washington's sanctions
@highlight
China and South Korea are likely to qualify for exemptions in the coming months
@highlight
Iran oil production has fallen to a 10-year low and could drop further
China, the biggest buyer of Iranian crude, usually accounts for one-fifth of Iran's crude exports but in February @placeholder's purchases plummeted to 290,000 barrels a day, a 40 per cent drop from the previous year.