U.S. President Barack Obama has signed an executive order that carries out new sanctions against Iran that Congress approved and that he signed this summer, said the NSC statement on the White House website.
White House National Security Council spokesman Tommy Vietor said in a statement that "this action is part of comprehensive sanctions effort to apply pressure on the Iranian government to meet its international obligations with regard to its nuclear program".
Vietor added that this "sanctions effort has produced profound and demonstrable results".
The sanctions seek to deter Iran from pursuing a nuclear weapons program, as many Western governments suggest it is doing. Iran insists its nuclear development is for peaceful purposes.
In August, the US Congress passed legislation that would expand sanctions to target individuals or companies who issue or purchase Iranian debt or who assist the Iranian government in the development or transportation of Iranian oil or its petrochemicals.
White House National Security Council spokesman also said that US President also issued today a memorandum that delegates certain Presidential functions and authorities in ITRSHRA to the Secretaries of State and the Treasury and other cabinet-level officials.
According to NSC Statement, "this Administration will continue to work with Congress to implement ITRSHRA in furtherance of our shared objective to prevent Iran from acquiring a nuclear weapon".
The International Monetary Fund (IMF) this week predicted that Iran's economy would shrink by 0.9 percent in 2012, in part due to international sanctions efforts that have targeted Iranian oil revenues.
But the IMF, whose forecast is based on what some say are questionable figures provided by Tehran, also suggested Iran would tame runaway inflation and get back to growth in 2013.
Iranian authorities have also been battling to prop up the Iranian currency, the rial, which has lost much of its value this year and sparked a recent crackdown on moneychangers.
Edited by: S. Isayev