Iran refused on Thursday to suspend its uranium enrichment activities as a precondition for negotiations to solve the nuclear issue, while warning it will react to any possible sanctions.

"Iran is of the belief that the right course of action in resolving the nuclear issue is through dialogue and negotiations, without preconditions," Ali Soltanieh, Iran's permanent representative to the International Atomic Energy Agency (IAEA), told a board meeting of the United Nations' nuclear watchdog.

The 35-nation board of governors of the IAEA wrapped up a regular session on Thursday, one day ahead of schedule.

Iran's nuclear issue was the hottest topic during the four-day meeting, with the discussion lasting from Wednesday afternoon to Thursday morning, when Iran was among the last four nations to make their statements.

"As always declared, Iran is fully prepared to remove ambiguities, if any, about its nuclear activities," Soltanieh said.

The United States and the European Union are warning Iran to return to the negotiating table or face more sanctions from the UN Security Council, but they insist that Iran should suspend its uranium enrichment first, as required by Security Council resolutions.

On March 24 the Security Council unanimously adopted a new resolution, the second punitive one, with tougher sanctions to pressure Iran to suspend its uranium enrichment activities.

However, an IAEA report two weeks ago said that Iran continued to resist the UN Security Council ban on enrichment and instead was expanding its activities.

The U.S. government made it clear on Monday that it will push for the third round of sanctions against Iran through the Security Council in response to Tehran's non-compliance.

"The Iran nuclear issue has to only be dealt with in the framework of the IAEA as the sole pertinent technical international organization," Soltanieh said, adding the engagement of the Security Council has further complicated the situation.

At a following press conference, Soltanieh indicated that Iran may reduce its cooperation with the IAEA if the Security Council approves new sanctions.

"After each (Security Council) resolution, each action, there is a reaction, a prompt reaction from Iran," he said. Asked about whether it means Iran will reduce cooperation with the UN. nuclear watchdog, Soltanieh said, "I said options are exhausted ... you have to read between the lines."

Iran partially stopped its cooperation with IAEA inspectors after the Security Council adopted the March resolution.

Soltanieh said Iran is now the master of uranium enrichment technology for fuel production, so there is no sense in suspension.

"Therefore let's be pragmatic, sit down together and Iran is fully prepared to ensure non-diversion of enrichment activities to prohibited purposes," he said.

The United States and some European countries accused Tehran of trying to develop nuclear weapons with its uranium enrichment project, an accusation Iran denies, saying it only wants it for electricity.