The United States joined its allies Britain and Canada in imposing another round of tough sanctions on Iran, targeting its central bank and energy sector, in what Secretary of State Hillary Clinton said was aimed at sending a clear message to Tehran of its increasing isolation.
The sanctions by Western nations came in response to a report by the UN atomic watchdog International Atomic Energy Agency about Iran's nuclear programme and after their proposal to impose new sanctions in the United Nations was blocked due to opposition from Russia and China.
US President Barack Obama signed an executive order on Monday that specifically targets Iran's petrochemical industry, and expands sanctions on Iran's oil and gas business; besides slapping sanctions on several individuals and entities in Iran.
Invoking the Patriot Act, the US identified the entire Iranian banking sector, including the Central Bank of Iran, as a threat to governments or financial institutions that do business with Iranian banks.
"The message is clear: If Iran's intransigence continues, it will face increasing pressure and isolation," Clinton told media persons joined by Treasury Secretary Timothy Geithner.
These steps were accompanied by complementary measures by Britain and Canada, she said, adding that US expects additional sanctions by other international partners in the days ahead.
"Together, these measures represent a significant ratcheting up of pressure on Iran, its sources of income and its illegal activities," Clinton said.