The U.S. could sanction European businesses that work with Iran, national security adviser John Bolton told CNN's Jake Tapper on Sunday.
Bolton's statement comes a day after Iran's foreign minister Mohammad Javad Zarif began a tour of the five nations still in the Iran nuclear agreement. Zarif hopes to redesign the deal without American involvement.
President Donald Trump withdrew the U.S. from the 2015 Iran nuclear agreement Tuesday. Britain, France, Germany, Russia and China are still signed on to the deal.
In a joint statement, the leaders of France, Germany and the United Kingdom said they remain committed to the deal.
Iran's president is also pushing for the deal to continue. President Hassan Rouhani said Sunday the country would remain in the deal if the other signatories continue to follow the agreement.
But there are those within Iran's government who are less certain of the agreement's longevity. A senior cleric and the head of Iran's revolutionary guard have warned against trusting foreign countries.
Additional reporting from Newsy affiliate CNN.