The United States on Thursday issued fresh sanctions targeting Iran in response to "continued nuclear escalations," U.S. Secretary of State Antony Blinken said in a statement.
"Over the past month, Iran has announced steps to further expand its nuclear program in ways that have no credible peaceful purpose," Blinken said.
"We remain committed to never letting Iran obtain a nuclear weapon, and we are prepared to use all elements of national power to ensure that outcome."
Iran's mission to the United Nations in New York did not immediately respond to a request for comment.
Thursday's action imposes sanctions on three companies based in the United Arab Emirates the U.S. accused of being involved in the transport of Iranian petroleum or petrochemical products, as well as 11 associated vessels.
Earlier this month, the Group of Seven rich nations warned Iran against advancing its nuclear enrichment program and said they would be ready to enforce new measures if Tehran were to transfer ballistic missiles to Russia.
Earlier in June, the U.N. nuclear watchdog's 35-nation Board of Governors passed a resolution calling on Iran to step up cooperation with the watchdog and reverse its recent barring of inspectors.
Iran is enriching uranium to up to 60% purity, close to the 90% of weapons grade, and has enough material enriched to that level, if enriched further, for three nuclear weapons, according to an IAEA yardstick.
Western powers say there is no credible civilian reason for that. Iran says its aims are entirely peaceful but officials have recently said it could change its "nuclear doctrine" if it is attacked or its existence was threatened by arch-foe Israel. That has prompted alarm at the IAEA and in Western capitals.
