"Now is not a suitable time to enter negotiations with the United States because it amounts to offense and humiliation," Motahari was quoted as saying by the Iranian Tasnim News Agency.
Motahari also reportedly noted that there would have been no problems with starting the negotiation process with Washington if the United States had not unilaterally exited and had not reimposed economic sanctions on Iran.
Meanwhile, Iranian Foreign Minister Mohammad Javad Zarif said Tuesday that Washington should blame itself for ending talks with Tehran when it withdrew from a nuclear deal. "US can only blame itself for pulling out and leaving the table," Mohammad Javad Zarif said in a tweet.
In May, Trump announced that the United States was pulling out of the 2015 Iran nuclear agreement, saying that the United States would reintroduce sanctions both against Iran and against the countries that continue to do business with Tehran.
Apart from the United States, the deal was also signed by Iran, China, France, Russia, the United Kingdom and Germany and provided for the relief of the economic sanctions against Iran in return for Tehran's keeping its nuclear program purely peaceful.
Another three resolutions had been adopted by the United Nations toughening the sanctions against Tehran before the Joint Comprehensive Plan was adopted.