VIENNA, Austria (AP) – Iran has exempted some centrifuges from an agreement to freeze uranium enrichment and related activities, the head of the U.N. atomic watchdog agency said Thursday, suggesting Tehran may intend to roll back its commitments.

Separately, Mohamed Elbaradei said Pakistan has agreed in principle to have his agency inspect some of its own nuclear equipment to test the veracity of Tehran’s claims about Iran’s nuclear program.

ElBaradei, head of the International Atomic Energy Agency, said his inspectors would be able to verify a suspension of all enrichment-related programs “with one exception” – centrifuges that Iran insists are not part of the freeze deal.

His comments to reporters at the start of an IAEA board meeting further complicated the issue of what to do about Iran, which agreed earlier this month to one of the agency’s key demands – the suspension of all uranium enrichment and related activities.

The last-minute Iranian attempts to roll back on its commitment – by demanding the right to run centrifuges for what it said were research purposes – fed fears that the Islamic republic may not be keen to ease concerns about its nuclear agenda. Enrichment can produce different grades of uranium that can be used either for fuel or as the core of nuclear warheads.

Iran’s push did not seem to represent a major move because thousands of centrifuges must operate for months to produce enough enriched uranium for a nuclear warhead.

But European diplomats said any determination by ElBaradei that the enrichment freeze was less than 100 percent could turn sentiment against Iran at the meeting and help the American case that Iran should be referred to the U.N. Security Council. A senior EU diplomat said Iran originally asked to be able to operate more than 100 centrifuges.

ElBaradei said the Iranians were now insisting that about 20 centrifuges be exempted. These, they said, could be monitored by the agency and would use “no nuclear material.”

ElBaradei suggested Iran might back down on the issue soon, telling reporters: “I hope that the remaining one issue on complete suspension would resolve itself in the next 24 hours or so.”