This dims prospects of an Israeli strike on Iran's nuclear facilities, the New York Times reported this week.

Israeli officials thought Iran could develop nuclear weapons within months. But Gary Samore, Barack Obama's top adviser on nuclear issues, told the Times he thinks it would take Tehran "roughly a year" to turn low-enriched uranium into weapons-grade material.

"A year is a very long period of time," said Samore.

The assessment is based on US intelligence and international inspectors' reports.

Israeli officials have indicated that if they thought Iran was developing a nuclear weapon, they would probably take military action. Iran claims it is enriching uranium only for peaceful purposes.

American and Israeli officials believe that Iran has only enough nuclear materials for two weapons. And to build those two would require the country to kick out international inspectors, which would make it clear what its intentions were.

It would also take some time for Iran to convert its nuclear facilities to produce weapons-grade uranium.

Iran has added relatively few centrifuges - machines that enrich uranium - this year, and only about half of those are working, according to the International Atomic Energy Agency.

"Either they don't have the machines or they have real questions about their technical competence," Samore told the Times.

n Iran's defence minister Ahmad Vahidi said military forces have successfully test-fired a missile with enhanced guidance systems to hit ground targets.

He did not disclose when or where the test was carried out.

His comments came a day before the start-up operations at the Bushehr nuclear power plant in southern Iran and could raise Western fears about another advance in Iran's missile arsenal.