Iran is pushing back against new sanctions imposed by the Trump administration on 18 individuals and groups.

Iran's Foreign Minister Javad Zarif says the Trump administration's rhetoric could jeopardize the landmark nuclear agreement. He spoke on Tuesday with CBS News correspondent Margaret Brennan about relations with the U.S. and the detention of two Iranian-Americans inside the notorious Evin Prison.

Baquer Namazi, 80, has been held for more than a year. His son, 46-year-old Siamak, was arrested in October 2015 on charges of collaborating with a foreign government.

They are among a handful of Americans currently detained in Iran. The country's top diplomat acknowledged that's not helping already tense relations.

Zarif says Baquer Namazi, who is in failing health, "is not behind bars" at this time but "he is not free to leave the country."

"The executive branch of the government does not have control over judicial decisions," Zarif added.

Namazi's attorney and the White House refuted Zarif's account as being "patently false." A Trump administration official told CBS News that both men have received "especially severe treatment" probably due to "their American citizenship" and accused Zarif of being either ignorant or attempting to deceive.

Zarif said U.S. authorities unfairly treat Iranian nationals. He also questioned why Mr. Trump sees Iran's rival, Saudi Arabia, as a key ally.

"The U.S. is basically arresting or asking for the arrest of Iranian nationals all over the world," Zarif said. "Whose nationals were involved in 9/11? Was there a single Iranian in every act of terrorism that has been committed against Americans on the U.S. soil since 2001?"

"If the answer is no, then they'll see that this policy that has been adopted by the president of the United States is an affront not only to Iranians, but to sensible human beings," he continued.

The Trump administration's heated rhetoric and recent sanctions on Iran are aimed, in Zarif's view, at undermining the Obama-era deal to freeze Iran's nuclear program.

Mr. Trump was reluctant to certify that Tehran is living up to what he calls a bad deal.

According to Zarif, the United States has been "in defiance of both letter and spirit of the nuclear deal," but he says Iran won't walk away because "there are procedures that are written into the deal."

"Its interesting for everybody to understand that this deal was not based on trust," Zarif said. "This deal was based on mutual mistrust."

Recent sanctions may be intended to poison the atmosphere and ultimately even sink the deal, according to Zarif.

The Trump administration is still reviewing its Iran policy, and for now, is sticking with strict interpretation of the agreement.