"The USD 4.2 billion in restricted Iranian assets that Iran will gain access to as part of the agreement will be released in regular installments throughout the six months. The final installment will not be available to Iran until the very last day," Secretary of State John Kerry said on Sunday. (Agencies)
A top official, however, said Iran will get the first installment of USD 550 million around first week in February.
Iran and the P5+1 group - the US, UK, Russia, China, and France plus Germany - sealed a six-month Joint Plan of Action in November last year. Under the plan, Iran agreed to curb parts of its nuclear programme for six months in exchange for modest relief from international sanctions.
Iran announced that it along with six world powers have agreed on how to implement the nuclear deal they struck in November with the terms starting from January 20.
"I have no illusions about how hard it will be to achieve this objective, but for the sake of our national security and the peace and security of the world, now is the time to give diplomacy a chance to succeed," Obama said in a statement.
"Today's agreement to implement the Joint Plan of Action announced in November marks the first time in a decade that the Islamic Republic of Iran has agreed to specific actions that halt progress on its nuclear programme and roll back key parts of the programme," he said.
Beginning January 20, Iran will for the first time start eliminating its stockpile of higher levels of enriched uranium and dismantling some of the infrastructure that makes such enrichment possible, Obama said.
"I welcome this important step forward, and we will now focus on the critical work of pursuing a comprehensive resolution that addresses our concerns over Iran's nuclear programme," he said.
However, some congressional lawmakers who are skeptical over the deal have proposed fresh sanctions against Iran.
Obama, however, cautioned them "imposing additional sanctions now will only risk derailing our efforts to resolve this issue peacefully."
"We will continue to vigorously enforce the broader sanctions regime, and if Iran fails to meet its commitments, we will move to increase our sanctions," he said.
"The USD 4.2 billion in restricted Iranian assets that Iran will gain access to as part of the agreement will be released in regular installments throughout the six months. The final installment will not be available to Iran until the very last day," Secretary of State John Kerry said on Sunday.