U.N. agency inspectors have been unable to watch surveillance footage and continue to deal with other challenges in monitoring Iran's rising uranium supply.
A U.N. agency said it was unable to specify exactly how large the cache has become because of restrictions imposed on. inspectors by Tehran earlier this year.
The expansion "probably indicates" North Korea will boost production of weapons-grade uranium, experts said.
Rouhani indicated that Iran could toughen relations with the West as President-elect Ebrahim Raisi prepares to replace him next month.
Ayatollah Ali Khamenei said the U.S. has "broken" its "promises tens of times, and it is the same now."
A study found levels of arsenic and uranium in private wells at concentrations higher than the Environmental Protection Agency's drinking water standards.
Authorities reportedly confirmed that none of the cargo material posed health threats after the accident took place on Wednesday.
Both the U.S. and Iran have said they will no longer adhere to the Obama-era Joint Comprehensive Plan of Action.
Known as the Detroit Dock, a site where uranium was processed for nuclear weapons partially collapsed into the already polluted Detroit River, causing concern from both U.S. and Canadian officials.
"The uranium is the wild card in that situation," one officer said.
An attempt by the European Union to keep Iran in compliance with a 2015 nuclear deal may have fallen short.
Piketon, Ohio, residents suggested a nearby gaseous diffusion plant might be responsible for the uranium.
A spokesman for the country's Atomic Energy Organization said Iran could resume its 20 percent uranium enrichment in under two days.
A spokesman for Hillary Clinton said the allegations are a distraction from the probe into Russian collusion in the 2016 election.
The very existence of the Havasupai tribe is at risk.
Its atomic energy spokesman said Iran would "take first retaliatory action immediately."
Saudi Arabia's former intelligence chief, Prince Turki al-Faisal, said the country would not give up its "sovereign" right to a civilian nuclear program.
Take a look at the Wall-E of Fukushima.
Republican lawmaker says Mueller "must step down immediately" because of ties to the Obama administration.
The head of Iran's Atomic Energy Organization warned of the country's capabilities amid mounting rhetoric between Tehran and Washington over the 2015 nuclear deal.
The Justice Department confirmed that the informant had been released from a confidentiality agreement.
The plan, code-named Nitro Zeus, was aimed at damaging Iran's air defenses, communications and power grid.
The country is believed to be working toward developing an intercontinental ballistic missile that can hit targets in the mainland U.S..