The International Atomic Energy Agency (IAEA), in its latest report, said that Iran has cut its most sensitive nuclear stockpile by nearly 75 percent in implementing the pact.
This means Tehran will have access to the next two installments, each of $550 million, which are due on May 14 and June 17. The final $550 million installment, due on July 20, is contingent on confirmation that Iran has fulfilled all of its commitment.
According to Reuters, the Indian government has asked refiners to make the first payment by mid-May, the sources said, adding that refiners will settle all three tranches if payment is allowed by the US and the European Union.
"The individual companies' share is to be worked out," one of the sources said.
Iran has so far received $2.55 billion in frozen oil funds, in five payments, four from Japan and one from South Korea.