The decision, which eases restrictions on trade in petrochemicals and precious metals and on the provision of insurance for oil shipments, among other measures, was expected to go into effect later in the day.
Earlier, a confidential UN atomic agency report obtained by Reuters stated that Iran has halted its most sensitive nuclear activity under a ground-breaking deal with world powers, paving the way for the easing of some Western sanctions.
The report by the International Atomic Energy Agency also said Iran had begun diluting its stockpile of uranium enriched to the fissile concentration of 20 percent - a level that took it closer to the capability of producing fuel for an atom bomb.
The IAEA report to member states said: "The Agency confirms that, as of 20 January 2014, Iran has ceased enriching uranium above 5 percent U-235 at the two cascades at the Pilot Fuel Enrichment Plant (PFEP) and four cascades at the Fordow Fuel Enrichment Plant (FFEP) previously used for this purpose."
It was referring to Iran's two enrichment plants, at Natanz and Fordow. Cascades are interlinked networks of centrifuge machines that enrich uranium. Iranian state television earlier said Iran had suspended 20 percent enrichment at Natanz and that inspectors were heading to Fordow.
The IAEA report also listed other measures Iran had agreed to under the interim accord with the six world powers - the United States, France, Britain, Germany, China and Russia.
Those included an undertaking that Iran would not build any more enrichment sites during the six-month agreement, a step meant to buy time for negotiations on a final settlement of Tehran's decade-old nuclear dispute with the six powers.
Enriched uranium can have both military and civilian purposes. Iran denies Western allegations that it has been seeking to develop the capability to make nuclear bombs, saying it wants only civilian atomic energy.
In turn, the European Union's foreign policy chief Catherine Ashton said on Monday she hopes a new round of negotiations with Iran on a definitive settlement to a decade-old nuclear standoff could start within a few weeks. REUTERS