TEHRAN, Iran — Iran's parliament approved a bill Sunday requiring the government to block international inspections of its atomic facilities if the UN nuclear monitoring agency refers Iran to the Security Council for possible sanctions.

The bill was approved by 183 of the 197 lawmakers present at the session, which was broadcast live on state-run radio. The vote came four days before the International Atomic Energy Agency board meets to consider referring Tehran for violating a nuclear arms control treaty.

When the bill becomes law, as is expected, it will strengthen the government's hand in resisting international pressure to abandon uranium enrichment, a process that can be used to produce fuel for nuclear reactors or an atomic bomb.

The United States accuses Iran of trying to build a nuclear weapon. Iran says its program is for generating electricity.

The bill will go to the Guardian Council, a hard-line constitutional watchdog, for expected ratification.

"If Iran's nuclear file is referred or reported to the UN Security Council, the government will be required to cancel all voluntary measures it has taken and implement all scientific, research and executive programs to enable the rights of the nation under the Nuclear Nonproliferation Treaty," lawmaker Kazem Jalali quoted the bill as saying.

Canceling voluntary measures means Iran will stop allowing IAEA inspections of its nuclear facilities and would resume uranium enrichment.

Iran resumed uranium reprocessing activities — a step before enrichment — at its Isfahan Uranium Conversion Facility in August but said it preferred a negotiated solution to begin uranium enrichment.

Under an additional protocol to the treaty, Iran has been allowing IAEA inspectors to carry out short-notice inspections of its nuclear facilities. Iran has signed the protocol but never ratified it.

The United States and European Union want Iran to permanently halt uranium enrichment. But Tehran says the nonproliferation treaty allows it to pursue a nuclear program for peaceful purposes, adding it will never give up the right to enrich uranium to produce nuclear fuel.

The 35-member IAEA board of governors meets Thursday. In a preparatory report, the UN agency found that Iran received detailed nuclear designs from a black-market network run by Abdul Qadeer Khan, the father of Pakistan's atomic program. Diplomats say those designs appear to be blueprints for the core of a nuclear warhead.

Khan's network supplied Libya with information for its now-dismantled nuclear weapons program that included an engineer's drawing of an atomic bomb.

The document given to Iran in 1987 showed how to cast "enriched, natural and depleted uranium metal into hemispherical forms," said the confidential IAEA report.

Iran sought Sunday to blunt potential international action over its nuclear program, labeling the report about its blueprints "baseless."

"This is just a media speculation," Iranian Foreign Ministry spokesman Hamid Reza Asefi said. "It is baseless."