Iran was set to receive the first $550 million installment in previously blocked overseas funds early this week as part of an interim nuclear deal, the United States confirmed on Monday.
Iran's official IRNA news agency earlier on Monday reported the money went into an Iranian Central Bank account in Switzerland. A U.S. Treasury spokeswoman confirmed the development by email.
Under a Nov. 24 nuclear agreement, six major powers agreed to give Iran access to $4.2 billion in its oil revenues frozen abroad if it carries out the deal. Tehran gets limited sanctions relief in exchange for steps to curb its nuclear program.
Iran says its nuclear program is solely for peaceful purposes, such as generating electricity and medical isotopes.
Some payments under the six-month deal - which officially began Jan. 20 - depend on Iran keeping its commitment to dilute half of its 20 percent enriched uranium to no more than 5 percent enriched uranium.
Iran cannot get its next installment of $450 million on March 1 unless the International Atomic Energy Agency confirms Tehran has done half the necessary dilution of its enriched uranium, according to a Treasury fact sheet.