The United States on Monday will sanction more than two dozen people and entities involved in Iran's nuclear, missile and conventional arms programs, a senior US official said.
Speaking on condition of anonymity, the official said Iran could have enough fissile material for a nuclear weapon by the end of the year and that Tehran has resumed long-range missile cooperation with nuclear-armed North Korea. He did not provide detailed evidence regarding either assertion.
A major part of the new US push is an executive order targeting those who buy or sell Iran conventional arms that was previously reported by Reuters and will also be unveiled by the Trump administration on Monday, the official said.
"Iran is clearly doing everything it can to keep in existence a virtual turnkey capability to get back into the weaponization business at a moment's notice should it choose to do so," the US official told Reuters.
The official argued Iran wants a nuclear weapons capability and the means to deliver it despite the 2015 deal that sought to prevent this by restraining Iran's atomic program in return for access to the world market.
In May 2018, Trump abandoned that agreement to the dismay of the other parties - Britain, China, France, Germany and Russia - and restored US sanctions that have crippled Iran's economy.
Iran, in turn, has gradually breached the central limits in that deal, according to the International Atomic Energy Agency (IAEA), including on the size of its stockpile of low-enriched uranium as well as the level of purity to which it was allowed to enrich uranium.
"Because of Iran's provocative nuclear escalation, it could have sufficient fissile material for a nuclear weapon by the end of this year," the official said without elaborating except to say this was based on "the totality" of information available to the United States, including from the IAEA.
"Iran and North Korea have resumed cooperation on a long-range missile project, including the transfer of critical parts," he added, declining to say when such joint work first began, stopped, and then started again.
The US official confirmed Trump will issue an executive order that would allow the United States to punish those who buy or sell conventional arms to Iran with secondary sanctions, depriving them of access to the US market.
The proximate cause for this US action is the impending expiration of a UN arms embargo on Iran and to warn foreign actors - US entities are already barred from such trade – that if they buy or sell arms to Iran they will face US sanctions.
Under the 2015 nuclear deal the UN conventional arms embargo is set to expire on Oct. 18.
The United States says it has triggered a "snap back," or resumption, of virtually all UN sanctions on Iran, including the arms embargo, to come into effect at 8 pm on Saturday/0000 GMT on Sunday.
Other parties to the nuclear deal and most UN Security Council members have said they do not believe the United States has the right to reimpose the UN sanctions and that the US move has no legal effect.
Among the targets will be Iran's "most nefarious arms organizations," about a dozen senior officials, scientists and experts from Iran's nuclear complex, members of a procurement network that supplies military-grade dual-use goods for Iran's missile program, and several senior officials involved in Iran's ballistic missile program, the US official said.
The official declined to name the targets, saying this would be made public on Monday, and stressed that the United States wants to deter foreign companies from dealing with them even if their governments believe this is legally permitted.
"You might have a split in some countries where a foreign government may claim that the UN sanctions don't snap back but their banks and companies will abide by US sanctions because they want to make sure they are not a future target," he said.