With the United States reimposing sanctions on Iran earlier this month that were lifted under the 2015 Iran nuclear accord, British Foreign Secretary Jeremy Hunt met with Iranian Foreign Minister Javid Zarif in Tehran on Monday to save the details of the deal.

The development comes as economic analysts say that sanctions have had an adverse affect on Iran’s economy.

Although the United States provided humanitarian exemptions, “far-reaching sanctions on Iranian financial firms reimposed two weeks ago could endanger the flow of humanitarian goods, as foreign banks and outside suppliers abandon business ties with their partners in Iran, warn analysts and experts,” according to the Associated Press.

The AP added that “in recent months, some European banks have refused to process payments even from Iranian firms that are exempt from sanctions out of fear of U.S. penalties, according to people familiar with the transactions.”

Hunt held other discussions with Zarif, including his country’s imprisoning of Iranian-British dual national Nazanin Zaghari-Ratcliffe, who will turn 40 years old on Dec. 26.

“If Iran has a policy of detaining dual nationals as a tool of diplomatic leverage then there will be consequences for Iran,” he said. “We will not let them get away with it scot-free. They have to understand this is not a sustainable situation.”