At their meeting in Bush's Texas ranch, Sharon urged the US leader to keep pressing Iran to give up its nuclear program altogether and cautioned not to follow Europe's softening stance in its talks with Iran that could end up allowing it to hold on to technology to enrich uranium.

The officials said Sharon spread photographs of Iranian nuclear sites -- first reported by Israeli public radio on Tuesday -- over a lunch table and told Bush that Israeli intelligence showed the Iranians were close to developing its own nuclear weapons technology.

Sharon told Bush that once Iran solves certain technical hurdles, there will be no way of stopping it from building a nuclear weapon, even if it does not do so immediately, the paper said.

A senior official travelling with the Israeli delegation said the UN Security Council needed to take immediate action against Iran in the form of sanctions.

"There has to be immediate action taken against Iran," he told reporters, warning that time was running out.

"There is a time limit because Iran will soon reach a technological point of no return. We are not talking about when Iran actually produces nuclear weapons but when it has the technological ability to do so," he said.

The issue needed to be immediately addressed by the Security Council, he said.

"Within this time frame, we have to take this to the Security Council -- they are a the only ones with the tools to do this," he said, referring to sanctions.

"Beyond this point of technological no-return, it will be too late."

Despite Sharon's urgency, US officials said the information he showed Bush was neither startling nor new.

"The Israelis consider the Iranians a big threat and they saw this as another opportunity to convey that to the president," a US official said, adding that among American experts familiar with the latest Israeli imagery "no one thinks this was earth-shattering stuff."

The United States and Israel have both accused Iran of using its atomic energy programme as cover for a plan to develop nuclear arms, a charge denied by Tehran which says it needs nuclear power as an alternative energy source.

Israel itself has never publicly acknowledged that it maintains a nuclear arsenal but foreign experts say it has between 100 and 200 nuclear warheads.

After the Bush-Sharon meeting Monday, White House spokesman Scott McClellan denied they had discussed the possibility of a preemptive military strike by Israel, aimed at ensuring Iran does not acquire atomic weapons.

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