Iran's parliament has passed a bill which obliges the government to review its co-operation with the United Nation's nuclear agency, the IAEA.
Iran's parliament approved the bill by an overwhelming majority
The move comes four days after the UN Security Council voted to impose sanctions on Tehran over its controversial nuclear programme.
After the UN vote, President Mahmoud Ahmadinejad said he would reduce co-operation with the IAEA.
Iran is likely to limit UN inspections of nuclear sites, correspondents say.
The UN sanctions, passed unanimously, include a ban on trade in nuclear-related technology, and a freeze on some Iranian assets.
The Security Council resolution demands that Tehran end all uranium enrichment work, which can produce fuel for nuclear plants as well as for bombs.
UN SANCTIONS ON IRAN
Ban on import and export of nuclear-related material
Assets frozen of 10 companies and 12 individuals
Threat of further non-military sanctions
The text of the Iranian bill was read out during a parliament session broadcast live on state radio: "The government is obliged to revise its co-operation level with the International Atomic Energy Agency (IAEA)."
The bill, which also tells the government to "accelerate" Iran's controversial nuclear drive, was approved by an overwhelming parliamentary majority.
Out of 203 deputies present, 161 voted in favour, 15 against and 15 abstained.
"The bill gives a free hand to the government to decide on a range of reactions - from leaving the Nuclear Non-proliferation Treaty to remaining in the International Atomic Energy Agency and negotiating," speaker Gholam Ali Haddad Adel said during the debate.
The bill was then approved by the Guardian Council, a hardline constitutional watchdog which vets all parliamentary legislation.
After the UN sanctions were passed on 23 December, Iran said it would immediately begin installing 3,000 centrifuges at a uranium enrichment plant at Natanz.
Traces of weapons-grade uranium were found at Natanz, in central Iran, during UN inspections in 2003, although this was later blamed on contaminated imported equipment.
Iran's plan to install centrifuges at the site would enable a vital stage of the process of enriching uranium into weapons-grade material.
It says its nuclear programme is for peaceful purposes only.