Israeli officials say no decision has been made on military action against Iran's nuclear programme, despite reports that the window for a pre-emptive strike is closing.
A government source told Sky News "all options remain on the table" but refused to comment on growing media speculation that a strike would take place by the summer of 2012.
Israel's defence minister Ehud Barak has warned that "time is urgently running out" to prevent Iran from developing nuclear weapons.
He said the Iranians are "deliberately drifting into what we call an immunity zone where practically no surgical operation could stop them."
Mr Barak was referring to Iran's efforts to move critical elements of its nuclear programme - including uranium enrichment - deep underground.
Iran's main enrichment site at Fordo, near Qom, is beneath 90 metres of rock, perhaps beyond the reach of even the huge bunker-busting bombs Israel is known to possess in its arsenal.
Tehran claims it is developing nuclear technology for civilian purposes but the latest report from the UN's nuclear watchdog said Iran was carrying out work that could only be related to the future development of a nuclear weapon. Read More