In wake of U.S. strikes, Iran faces a pivotal choice: dash to build a weapon or negotiate

Hiding key Iranian nuclear facilities deep under a mountain made them that much harder for U.S. and Israeli weapons to reach.   

It will also make it more difficult to assess just how successful the historic U.S. strikes against them overnight Saturday were and more challenging to predict Iran's next steps. 

In his statement moments after the U.S. attack by B-2 bombers and their deep-penetrating almost 14 tonne bombs, U.S. President Donald Trump was unequivocal in his claim:    

"Iran's key nuclear enrichment facilities have been completely and totally obliterated," he said.     

Israeli Prime Minister Benjamin Netanyahu sounded equally conclusive, claiming his promise to destroy Iran's nuclear facilities had been "fulfilled."

Yet, within hours, Iranian officials were giving Reuters news agency a conflicting account, claiming that most of the highly enriched uranium at Fordow had been moved elsewhere before the attack.  

Fordow is Iran's main site for enriching uranium, with some of the stockpile there having been enriched to about 60 per cent in the assessment of the International Atomic Energy Agency, charged with monitoring Iran's nuclear facilities. Ninety percent enrichment is considered weapons capable.

"The degree of damage inside the uranium enrichment halls can't be determined with certainty," IAEA director General Grossi said Sunday of the strike on Fordow.

The sprawling Isfahan site, which had already been struck several times since Israel's strikes began June 13, also suffered "extensive additional damage" in the U.S. operation, the agency said.

The IAEA had reported on Saturday that the facilities at Isfahan bombed by Israel either contained no nuclear material or small quantities of natural or low-enriched uranium, an indication that the highly enriched uranium might be stored elsewhere.

In his morning-after briefing, General Dan Caine, the head of the U.S. Joint Chiefs of Staff, said the three targeted sites had sustained "extremely severe damage and destruction," but he acknowledged a final damage assessment would take some time.

He said the operation was "the largest B-2 operational strike in U.S. history."

But Daria Dolzikova, with the Royal United Services Institute, a London-based military think tank, said it might not be enough to destroy Iran's nuclear program.

"The fundamental reality remains that military action alone can only roll back the program by degrees, not eliminate it fully," she said.