Iranian Foreign Minister Mohammad Javad Zarif
Iranian Foreign Minister Mohammad Javad ZarifReuters

Tehran said Sunday it will keep talking with world powers on its disputed nuclear program despite a U.S. move to blacklist Iranian companies for evading sanctions, AFP reported.

“We are pursuing the negotiations seriously and of course we will give a well-considered, purposeful, smart and proper reaction to any inappropriate and unconstructive move,” Foreign Minister Mohammad Javad Zarif was quoted as having written on his Facebook page.

This was despite the Americans having made “inappropriate moves to which we gave the appropriate response by considering all aspects of the issue,” said Zarif.

“The negotiations and achieving a result are a difficult task and will definitely have a lot of ups and downs. We have predicted that from the very beginning,” he added.

The comments came after the United States blacklisted a dozen overseas companies and individuals on Thursday for evading its sanctions imposed on Iran to halt what the West sees as its bid to build a nuclear bomb.

Senior U.S. officials argued the move was taken under an existing sanctions regime which had forced Tehran to negotiations that led to an interim deal under which it agreed last month to freeze parts of its nuclear program.

The measures, which angered Iran and prompted its negotiating team to withdraw from the talks in Vienna, have drawn strong criticism in the Islamic Republic.

Zarif vowed to answer at the right time domestic critics who were using his “necessary silence” to voice their displeasure at the nuclear deal reached with the six world powers in Geneva on November 24.

“Some friends who were not happy with the Geneva joint action program have already announced its premature death, which is more the expression of their desire rather than the truth,” he said on Facebook, according to AFP.

“The negotiating team has a more important responsibility... and is ready to remain silent against unjust and unfair accusations for the sake of national interests, but will answer to all the criticism and ambiguity at the right time.”

The blacklisting of the companies on Thursday 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.

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.

Zarif has previously warned that if the United States imposes any new sanctions on his country, the nuclear deal reached in Geneva would be “dead”.