Iran's top nuclear negotiator Ali Larijani speaks during the International Conference on Iran's Nuclear Policies and Prospects in Tehran yesterday. -Xinhua

Iranian top nuclear negotiator Ali Larijani said yesterday that Iran would stop acting transparently over its nuclear program if attacked.

Larijani also said at a conference on the Iranian nuclear program in Tehran that the Islamic Republic would halt its relations with the International Atomic Energy Agency (IAEA) if the UN Security Council imposes sanctions.

"In case of sanctions, Iran will suspend its relations with the agency," Larijani said.

"If Iran is attacked militarily, we cannot be expected to act transparently (concerning the nuclear program)," he added.

"Those Western countries (on the IAEA board) have to understand that the (nuclear) issue cannot be resolved by force," Larijani stressed.

Larijani also said there was no reason to halt Iran's nuclear program.

"Iran only has 164 centrifuges now, can these make an atomic bomb? We don't understand why we should suspend. Suspend what?" he complained.

The top nuclear negotiator made the statements ahead of a Friday UN deadline demanding Iran to stop all uranium enrichment activities.

Based on a Feb. 4 resolution, the IAEA on March 8 handed over the Iranian nuclear issue to the UN Security Council.

After weeks of heated bargains, the 15-member Security Council on March 29 approved a non-binding presidential statement, asking Iran to suspend uranium enrichment activities in 30 days and demanding the UN nuclear watchdog to report on Tehran's compliance.

Mohamed ElBaradei, chief of the IAEA, is expected to submit the report to the Security Council in the coming days.

With the deadline looming, Iran's hardline President Mahmoud Ahmadinejad said on Monday that he believed sanctions were unlikely, vowing to press ahead with the nuclear program.

He also warned that Tehran would "reconsider" its cooperation with the IAEA, hinting a possible withdrawal from the nuclear Non-Proliferation Treaty, if western countries continued to prevent Iran from obtaining peaceful nuclear technologies.

Earlier this month, Iran officially declared that it had gained ticket to joining the global nuclear club by having produced 3.5 percent enriched uranium, a technological leap in the process for nuclear power plant construction, which immediately aroused strong international concern.

The United States has accused Iran of secretly developing nuclear weapons under a civilian front, but Iran dismissed the charge, saying that its nuclear program is fully peaceful.