A top U.S. security official is due to meet Sunday with Israeli Prime Minister Benjamin Netanyahu, amid rising tensions between Israel and Iran over Tehran's nuclear program.

The White House says National Security Advisor Tom Donilan will hold talks with Mr. Netanyahu in Jerusalem.

The meeting comes as the chairman of the U.S. Joint Chiefs of Staff, General Martin Dempsey, says an Israeli attack on Iran's nuclear facilities would not be “prudent.” In an interview to be broadcast Sunday, the general told CNN a military strike would be “destabilizing” and would not achieve Israel's long-term objectives.

Donilan is the latest in a series of American officials to discuss the Iran issue with Israeli leaders.

Speculation has swirled in recent weeks that Israel is preparing to launch a preemptive strike on Iran's atomic facilities.

In another development, diplomats say Iran is ready to expand its uranium enrichment program at an underground facility to where it could come closer to making a nuclear weapon.

The Vienna-based diplomats – speaking on the condition they remain anonymous – say Iran is poised to install thousands of new centrifuges at its Fordo enrichment site – a complex built inside a mountain near the northern city of Qom.

The new centrifuges could speed up the production of enriched uranium, which can be used to make atomic weapons if the uranium is a very high grade.

Inspectors from the International Atomic Energy Agency are due to visit Iran Monday.

Iranian state media reported last week that President Mahmoud Ahmadinejad was set to formally declare the Fordo site “fully operational.” Iran also unveiled what it said are a new generation of centrifuges at a uranium enrichment plant in the central city of Natanz.

The United States, Israel and other countries suspect Iran's nuclear program is aimed at producing atomic weapons, a charge Iran denies.

Israel and the United States have said all options are open to prevent Iran from getting nuclear weapons.

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