Washington, Feb 19 (DPA) The US found many worrying revelations in a new report from a global nuclear watchdog Thursday that for the first time acknowledges Iran could be developing a nuclear warhead.

The Vienna-based International Atomic Energy Agency (IAEA) said it had a 'broadly consistent and credible' body of information about Iranian nuclear activities and said Tehran could be developing nuclear payload for a missile.

'A lot of concerning things from this report,' US State Department spokesman P.J. Crowley told reporters in Washington. The US and Western powers have long accused Iran of seeking nuclear weapons, a claim Iran denies.

The IAEA also said Iran was not cooperating with its investigators and had yet to provide information about a new enrichment site near Fordow, which was revealed only in September and raised fresh questions about whether Iran had a secret nuclear weapons programme.

'There is no explanation for that facility that is consistent with the needs of a civilian nuclear programme,' Crowley said. 'And it characterizes the way in which Iran has conducted its relations with the IAEA and its failure to satisfactorily explain ... what its activities and ambitions are in the nuclear sphere.'

While President Barack Obama's administration sought last year to engage Iran in talks about its nuclear activities, the US has this year been holding talks with global powers about another possible round of UN sanctions against Iran for failing to answer the international community's concerns.

'We're working with our international partners to ensure that Iran ... faces real consequences for failing to meet its international obligations,' US Vice President Joe Biden said earlier Thursday in a speech about non-proliferation before the National Defence University in Washington.