The United States will sanction more than two dozen people involved in Iran's weapons programs on Monday (September 21), depriving them of access to the U.S. market.
That's according to a senior U.S. official source who spoke to Reuters.
The Trump administration suspects Iran of seeking nuclear weapons - something Tehran denies - and Monday's punitive steps are the latest in a series of actions aimed at stopping Iran's nuclear program, which U.S. ally Israel views as an existential threat.
The official source said Iran could have enough fissile material for a nuclear weapon by the end of the year.
They also said Tehran has resumed long-range missile cooperation with North Korea, which already has nuclear arms.
The U.S. official didn't provide detailed evidence for either claim.
That's despite the 2015 Iran nuclear deal that sought to restrain the country's nuclear program in exchange for access to the world market, an agreement that U.S. President Donald Trump abandoned three years later to the dismay of the other countries involved.
According to the International Atomic Energy Agency (IAEA), Iran has gradually breached the central limits in that deal since Trump's withdrawal.
Monday's new sanctions fit into Trump's effort to limit Iran's regional influence, and come a week after U.S.-brokered deals for the United Arab Emirates and Bahrain to normalize ties with Israel.
They also put teeth behind U.N. sanctions on Tehran set to expire next month under the 2015 deal, which Washington now argues have resumed despite the opposition of allies and adversaries.
A spokesman for Iran's mission to the United Nations dismissed the official's statements on the new sanctions as propaganda -- and said they would further isolate the United States.
The White House declined comment ahead of Monday's announcements.