President Barack Obama's top military adviser will arrive in Israel this week amid deepening fears in Washington that the country is planning a pre-emptive strike against Iran's nuclear facilities.
The visit follows efforts by Mr Obama and his officials to warn Jerusalem against any unilateral military steps that would undermine sanctions against Iran and trigger far-reaching regional consequences.
General Martin Dempsey, chairman of the US Joint Chiefs of Staff, will meet military and intelligence officials, including Defence Minister Ehud Barak, during a trip that Israel's media has interpreted as an effort to sound out the Jewish state's intentions towards Iran.
News of the visit came as the Foreign Secretary William Hague refused to rule out military action in retaliation for what the West believes is Tehran's attempts to manufacture a nuclear weapon.
"We believe all options should be on the table," he said. "That is part of the pressure on Iran, but we are clearly not calling for or advocating military action." Mr Hague said the UK would seek tougher economic sanctions against the country.
Israel views Tehran's nuclear ambitions as an existential threat. Its increasingly strident rhetoric has stoked fears it could resort to a military strike if it considers diplomatic efforts to isolate Iran have failed.
The Wall Street Journal reported at the weekend that US officials were making contingency plans for a possible Israeli strike amid fears Jerusalem could go it alone without the green light from Washington.
In a phone conversation last week, Mr Obama is understood to have warned Israeli Prime Minister Benjamin Netanyahu against such a move to allow time for diplomatic pressure and sanctions to work.
But an official in Mr Netanyahu's cabinet yesterday criticised the US for failing to follow Europe's lead in pushing for tougher sanctions.
The official hinted Israel may have to take matters into its own hands by suggesting that Mr Obama was constrained by "election-year considerations".