Iranian oil ministry's official confirmed oil exports' decline because of the West sanctions over Iranian oil purchase and banking system.
Director of international affairs for the National Iranian Oil Company, Mohsen Ghamsari, told Iranian Shargh Daily News that Japan practically decreased Iranian oil purchase.
According to Japan's Industry Ministry statistics, Japanese companies have decreased Iranian oil imports from January to April by 28 percent.
Earlier, Reuters reported that Japan, South Korea and China have decreased Iranian oil imports by 22 percent in total.
Reuters reported on April 4 that Japanese companies shy away from renewing annual oil contracts with Iran as well.
According to the European Union's new sanctions on Iranian oil imposed on Jan.24, the Union will cut Iranian oil import completely by July 1.
On April 6, Iranian Press TV reported that the country has cut oil export to Greece refineries, because of occurred payment problems.
Greek Hellenic Petroleum and Motor Oil Hellas announced that they failed to pay off debts on Iranian oil import because of sanctions.
Mehrdad Emadi, one of the EU economic advisers, told Trend that Greece had imported 140, 000 barrels per day of Iranian oil (directly or via Cyprus) during January.
Greece which is suffering from economic crisis had imported about a half of its oil demands from Iran during the second half of last year.
South Africa, which imported 4 percent of Iranian exported oil, cut Iranian oil imports recently.
Ghamsari said that Iran is negotiating with South Africa about keeping on the oil deal.
Iran's crude oil production could fall by 1 million barrels per day by the end of June to below 2.5 million bpd, JPMorgan said in note on Thursday, saying refiners have cut demand for oil from the Islamic Republic faster than previously expected, Reuters reported.
According to OPEC statistics, Iran produced about 3.424 million barrels of oil per day in March, indicating 37, 000 barrels drop comparing the figure of oil output in January.