“If Iran continues to refuse to conduct serious negotiations on its nuclear
programme, new, more severe sanctions would be inevitable," German Foreign Minister Guido Westerwelle said, calling the report “alarming.”
He added that discussions with European partners and allies were underway, although he ruled out any military response.
France demanded unprecedented UN Security Council sanctions if Iran's defiance continued, the EU said its concerns were seriously aggravated and even ally China said Iran must be sincere after Tuesday's searing IAEA report.
The International Atomic Energy Agency said it had "serious concerns regarding possible military dimensions to Iran's nuclear programme," prompting Tehran to insist it would "not budge an iota" from its nuclear path.
US Republican hawks demanded "crippling" economic retaliation, while a senior US official cautioned that the report did not offer definitive answers about the current state of Iran's alleged drive for nuclear bombs.
"We don't take anything off the table when we look at sanctions. We believe there is a broad spectrum of action we could take," a senior US official said on condition of anonymity.
The European Union said the report "seriously aggravates" existing concerns over a military dimension in Tehran's nuclear programme.
"Overall these findings strongly indicate the existence of a full fledged nuclear weapons development programme in Iran," said Maja Kocijancic, spokeswoman for EU foreign policy chief Catherine Ashton.
Ashton represents six world powers – Britain, China, France, Germany,
Russia and the United States – in stalled negotiations with Iran aimed at
convincing Tehran to freeze its uranium enrichment activities.