Nasseri said Iran was "prepared to continue negotiations with the EU-3 (Britain, France and Germany)... as long as there are no preconditions" and the talks are in "good faith."

He was speaking after an emergency meeting of the UN watchdog International Atomic Energy Agency (IAEA) called by the EU-3 following Iran's resumption of uranium conversion work on Monday.

The process is the first stage in making fuel for nuclear power reactors, but can also be used to make the explosive core of atom bombs.

Nasseri said Iran was "frustrated" that after two years of talks, the EU-3 were still not acknowledging what Iran considers its right under the nuclear Non-Proliferation Treaty (NPT) to make nuclear fuel as part of a peaceful atomic program.

In Tehran, atomic energy agency chief Mohammad Saidi said IAEA seals placed on Iran's nuclear conversion plant in Isfahan should be broken by midday Wednesday.

IAEA inspectors "finished installing their surveillance cameras" on the plant on Tuesday, he said.

He said the agency had promised Tehran that the seals placed on the machinery would be lifted "by Wednesday midday."

But in Vienna IAEA spokeswoman Melissa Fleming said the Iranians would be breaking the seals, watched by IAEA inspectors.

Breaking the seals is the next crucial stage at the plant after Iran resumed suspended uranium conversion activities on Monday, sparking warnings of an international crisis.

In France, Foreign Minister Philippe Douste-Blazy said: "It is still possible to negotiate" with Iran on its nuclear activities. "We are still holding out our hand," he told journalists.