Japan made a second payment to Iran for crude imports under an interim nuclear deal on Wednesday, diplomatic sources told Reuters, as the West eases a year-long stranglehold on revenues that has crippled the Iranian economy.

Japan, which became the first of Iran’s oil buyers to make a payment to Iran last month, deposited $450 million in funds owed for oil imported from Iran in a Central Bank of Iran (CBI) account, according to the sources.

Tough international sanctions over the past two years cut Iran’s oil exports in half, while U.S. measures imposed a year ago stopped the remaining importers of Iranian oil from transferring cash to Tehran, starving Iran of hard currency and forcing it to the negotiating table over its disputed nuclear program.

Under a Nov 24 agreement with six major powers, Iran won access to $4.2 billion of its oil revenues frozen abroad by eight money-transfer schedules through July if it carried out its part of the deal to curb its nuclear program.

Japan last month became the first of Iran’s oil buyers to make a payment for crude imports under the deal, sources told Reuters, with one source confirming the amount of $550 million.

According to the agreement, the second and third payment schedules were March 1 for $450 million and March 7 for $550 million.

Tokyo’s role in sending the first two funds may be a boon for Japanese firms jostling for position with international rivals to invest in Iran’s oil and gas sector, should a further agreement end Tehran’s international isolation.

Iranian oil ministry news service Shana reported a senior official as saying on Tuesday that India has deposited some of the money owed for oil imported from Iran in a CBI account, but government and industry sources in India denied the report.

Indian officials said late last month that they were ready to pay $1.5 billion to clear part of a backlog of payments for shipments of oil following the partial easing of sanctions.

Source:Reuters