Iran's April crude exports will rebound to above 1 million barrels per day (bpd), industry sources said on Friday, after falling in March to the lowest level seen since the West imposed sanctions to reduce the oil flow in 2012.

U.S. and European Union sanctions aimed at choking the flow of oil money into Iran and forcing Tehran to negotiate curbing its disputed nuclear programme have cut around a million barrels per day from Iran's crude exports.

Iran is expected to export 1.08 million barrels per day (bpd) of crude in April, preliminary data obtained by Reuters showed, up from the 810,000 bpd that was scheduled to load in March and close to export levels of around 1.1 million bpd in February. The volumes are based on preliminary loading plans and final export volumes may vary.

Asian refiners buy the bulk of Iran's reduced export volumes and have steered clear of U.S. sanctions by steadily reducing imports. Despite the rise in April loadings, Iranian oil exports will still be down 36 percent on the year. Exports will likely drop further this year as buyers reduce imports as required by U.S. sanctions.

"Given that U.S. sanctions are likely to tighten further, exports from Iran are not going to be rising," said Victor Shum, oil consultant at IHS in Singapore. "I don't expect this rebound (in Iranian oil exports) to be sustained."   

The biggest month-on-month jump is from South Korea, which will triple imports in April to about 190,000 bpd as refiner SK Energy returns to contracted Iranian import volumes after shutting down a refinery for maintenance, a company source said.
   
Japan will also increase imports in April from March as some refining units are due to restart by late May after maintenance. Its April volumes will likely more than double from the same month a year ago when uncertainty over sanctions caused imports to plunge.

China, Iran's top customer, is expected to lift 415,000 bpd of crude in April, up from 379,000 bpd in the previous month.Taiwan will resume Iranian oil imports for the first time this year.

Indian refiners Indian Oil Corp and Essar Oil are scheduled to lift 3.7 million barrels or 123,000 bpd of crude in April, the data showed, but it is unclear what they will actually buy after insurance companies said they could not cover plants using Iranian oil.

The other two Iranian crude buyers in India, Mangalore Refinery and Petrochemicals and Hindustan Petroleum Corp, have said they will import none this month while they wait for clarification from the Indian government on how they can insure their refineries if they run Iranian crude.