TOKYO - Iran should freeze all its uranium enrichment-related activities by a November 25 board of governors meeting of the International Atomic Energy Agency (IAEA), the head of the U.N. nuclear watchdog, Mohamed ElBaradei, said on Friday.
But ElBaradei added that he was hopeful Iran would comply by then and even if it did not the matter would not automatically be referred to the U.N. Security Council for possible sanctions.
"I'm still hoping that before the meeting of the board that Iran will come into full suspension" of its uranium enrichment-related activities, ElBaradei told a news conference.
The IAEA board of governors passed a resolution last month demanding that Iran freeze all activities connected with uranium enrichment, including making feed material for centrifuges.
Earlier on Friday, ElBaradei said his agency had not detected any signs that Iran was using its nuclear programme to make weapons, but that he was still concerned.
Iran said on Wednesday it had processed several tonnes of raw "yellowcake" uranium to prepare it for enrichment -- a process that can be used to make nuclear weapons -- in defiance of the IAEA.
ElBaradei said Iran's assurances that it was not developing atomic weapons needed to be verified by IAEA inspectors.
"Our job is to verify that the assurances are reflected on the ground," he said after giving a speech in Tokyo.
ElBaradei, tipped as a potential winner of the Nobel Peace Prize, to be announced later on Friday, said the IAEA was making good progress in monitoring Iran's nuclear activities.
But he said it was too early to say that concerns about Iran's nuclear programme had been cleared completely.
"We have not completed our job to be able to say that no undeclared activities exist in Iran," he said.
Iran has said it will not yield to foreign pressure aimed at stopping what it says is a peaceful energy programme, but which Washington says is a covert scheme aimed at building bombs.
An IAEA spokeswoman in Vienna said on Wednesday that the uranium processing was being closely monitored by the agency to ensure that nothing would be diverted for weapons purposes.
It was unclear how much processed uranium had been produced so far, though Iran's chief delegate to the IAEA, Hossein Mousavian, indicated the amount was not large.
Iran's uranium conversion plant at Isfahan intends to process a total of 37 tonnes of yellowcake, which experts say could be enriched into material for up to five atomic weapons.
Tehran had originally promised France, Germany and Britain in October 2003 that it would suspend its entire enrichment programme and all related activities.
While it has yet to enrich any uranium, Iran never entirely froze the programme and recently resumed key parts of it.
If Tehran fails to heed the demands, the board has said it will consider possible "further steps" when it meets next month.
Diplomats on the board said this included possibly referring Iran to the U.N. Security Council, which can impose sanctions.
ElBaradei declined to say if the IAEA should refer Iran to the Security Council or whether it should set a deadline for Tehran to halt its nuclear programme.
ElBaradei arrived in Tokyo on Wednesday for a four-day visit.