Bushehr nuclear power plant in southern Iran
Bushehr nuclear power plant in southern IranAFP photo

Washington on Thursday blacklisted a dozen overseas companies and individuals for evading sanctions on Iran, AFP reports.

Under the designations, U.S. citizens or companies are barred from engaging in transactions with any of the targeted firms and individuals whose assets will be frozen in the United States.

"Today's actions should be a stark reminder to businesses, banks and brokers everywhere that we will continue relentlessly to enforce our sanctions, even as we explore the possibility of a long-term, comprehensive resolution of our concerns with Iran’s nuclear program," David Cohen, Treasury undersecretary for terrorism and financial intelligence, was quoted by AFP as having said.

Those listed include the Singapore-based Mid Oil Asia and Singa Tankers, both companies accused of helping Iran transfer badly-needed funds to a foreign bank on behalf of the National Iranian Tanker Company.

Ukrainian national Vitaly Sokolenko and his Odessa-based firm Ferland Company Limited were also cited for helping to broker the sales of Iranian oil and transfer the crude ship-to-ship.

The surprise blacklist announcement, seen as a clear warning to Tehran to comply with a nuclear deal, came as two top senators bowed to White House pleas not to introduce new sanctions.

The pair acknowledged more sanctions could "rupture" unity among global powers seeking to rein in Iran's suspect nuclear enrichment program.

"Let me be clear. I support strong sanctions, and authored many of the U.S. sanctions currently in place," said Senate Banking Committee chairman Tim Johnson, who has been in the spotlight over whether he would introduce a new sanctions regime this year, as several senators have sought.

"But I agree that the administration’s request for a diplomatic pause is reasonable," Johnson was quoted as having told a hearing.

Earlier this week, Johnson said that “The president and Secretary Kerry have made a strong case for a pause in congressional action on new Iran sanctions”, explaining his decision to hold off on new passing new sanctions legislation.

House lawmakers have admitted that a new Iran sanctions measure currently under consideration by the Senate is “all but dead in the water” and have expressed anger at their Senate counterparts for failing to pass the new sanctions legislation.

The fact that Senators are holding off on the sanctions is a victory for the Obama administration, which has waged an aggressive campaign to convince lawmakers to postpone passing new sanctions on Iran.

This campaign has included threats that Iran would make progress in its ability to build a nuclear weapon if there is no diplomatic deal, and warnings that passing new sanctions on the Islamic Republic would lead to war.

Senate Democrat Robert Menendez and Republican Mark Kirk have also been drafting a bill that they want to see passed sooner rather than later imposing tough new economic sanctions if Iran reneges on the six-month accord. So far they have not indicated that they too are backing down, but Senate officials have indicated that it’s unlikely the bill will be passed before the end of December.

Officials said the timing of Thursday's designations were coincidental and not aimed at sending a message to Congress to back off new sanctions.

The U.S. State Department also named five Iranian entities and several people that it alleges provide goods and services that contribute or risked contributing to Iran's nuclear program or its development of ballistic missiles.