The US Congress has overwhelmingly passed tough new sanctions against Iran, targeting the Islamic Republic's powerful Revolutionary Guards and country's imports of gasoline and other refined energy products.
The bill now goes to the White House for President Barack Obama's signature.
The Senate and House of Representatives in quick succession passed the Comprehensive Iran Sanctions, Accountability and Divestment Act. The House passed it by 408 to 8.
Businesses that help supply Iran with refined petroleum or help develop the country's own refining capacity would be penalised by the legislation.
In addition, the Islamic Revolutionary Guard Corps comes under more scrutiny.
Any financial institutions found to be doing business with the Guard or with blacklisted Iranian banks could be denied access to the US financial system under the bill.
"The Senate is taking an important step forward today as we pass a conference report that will impose tough new sanctions on Iran. We are passing these sanctions because we believe we must stop Iran from developing a nuclear weapon -- a weapon that would surely threaten the national security of the US and of Israel," said Senate Majority Leader Harry Reid.
"Our goal is to target Iran where it will hurt the regime the most. These new economic sanctions are related to Iran's refined petroleum sector and international financial institutions that do business with Iran's Islamic Revolutionary Guard and Iranian banks," he said.
"Today with the passage of this legislation and when it goes to the President's desk to be signed, we give the President new tools to: impose sanctions against companies that sell Iran technology, services, know-how, and materials for its energy and petroleum sector
"We offer foreign banks a choice -- they can deal with institutions that support weapons of mass destruction and terrorist activities, or they can do business with the United States," House of Representative Speaker Nancy Pelosi said in her speech on the floor of the house.
"These sanctions send a forcefully clear message to Iran about the growing costs of its self-imposed isolation. They build on the ones recently approved by the Security Council, on the European Council's declaration last week, and on the actions the Administration took to sanction new entities, tied to the Iranian Revolutionary Guard Corps and Iranian shipping and financial sectors, last week," House Majority Leader Steny H Hoyer said.
Senator John Kerry, Chairman of the Senate Foreign Relations Committee, said the bill moves the US closer toward accomplishing the shared goal of Congress, the administration, and the international community -- to bring maximum leverage to bear on Iran to change its behaviour and abandon its nuclear weapons ambitions.
"In particular, this legislation targets businesses involved in refined petroleum sales to Iran, support for Iran's Revolutionary Guard Corps, and Iran's nuclear programme. It imposes strong penalties on those in the Iranian government who have abused the rights of their own people. It tightens the enforcement of those sanctions already on the books. And it takes important steps to ensure that companies receiving US government contracts are not also doing business that enables, directly or indirectly, Iran's nuclear programme," Kerry said.
"The Congress will be sending to the President a long list of sanctions to implement. If all are implemented vigorously, this legislation could constitute decisive action to compel the Iranian regime to end its nuclear weapons pursuit, end its chemical and biological weapons and missile programmes, end its state-sponsorship of global jihadists," said Republican leader Ileana Ros-Lehtinen.
With the passage of the bill, the US is finally poised to inflict real damage to Iran's economy if it continues its nuclear program, said Senator Benjamin L Cardin.
"Along with the new, multilateral sanctions approved by the United Nation's earlier this month, we now have a better chance to prevent Iran from becoming a nuclear threat to Israel, the United States and the world.
"Iran has remained defiant, however, leaving few options beyond a unified and forceful implementation of an economic sanctions regime, along with rigorous enforcement, to stop them from moving further down their current, dangerous path," he said.
