Iranian lawmakers today voted to oblige their government to stop allowing snap UN checks of atomic sites and to resume uranium enrichment if Tehran is sent to the UN Security Council.
In the vote, broadcast live on state radio, 183 out of 197 lawmakers present voted for the bill. The legislation must now be approved by Iran's constitutional watchdog, the conservative 12-man Guardian Council.
Iran faces referral to New York for possible sanctions after failing to convince the world its atomic scientists are focusing on power stations rather than warheads.
The board of governors of the International Atomic Energy Agency (IAEA) will meet in Vienna on Thursday to decide on what steps to take with Iran's case.
Lawmaker Alaeddin Boroujerdi, head of parliament's foreign policy and security commission, exhorted opposition parliamentarians from the reformist camp to show a united front in the national interest.
"This is not a factional, political issue - it is a national issue," he said in the debate.
The bill calls for Iran's government to stop following the Additional Protocol to the nuclear Non-Proliferation Treaty, which allows snap U.N. checks of atomic sites.
It also calls on Iran to resume all activities that it stopped voluntarily. Foremost among these is the moratorium on enriching uranium.
Despite Western pressure on it to halt nuclear activity, Iran earlier this week said it had begun processing a new batch of uranium. Iran insists on developing its own nuclear fuel cycle to produce fuel for power stations.
But Washington fears Iran will enrich uranium to a high, weapons-grade level, rather than the low level needed for power stations such as the one it is building with Russian help at the Gulf port of Bushehr.
Gholamreza Aghazadeh, the head of Iran's Atomic Energy Organisation, attended the parliament meeting and said the bill gave a clear message to the IAEA.
"If the board of governors transgresses people's rights, nations are entitled to preserve their rights," he said.
Iran's chief atomic negotiator Ali Larijani has previously threatened to end snap checks and resume enrichment if Tehran's case is sent to New York.
But parliament's bill turns this threat into law which the government must follow.