(Newsroom America) — U.S. defense officials are making contingency plans to safeguard American facilities in the Middle East as Israel appears to be preparing to launch military strikes against Iran over its nuclear program.

The Wall Street Journal reported Sunday that President Barack Obama, Defense Secretary Leon Panetta and other top officials have warned Israeli counterparts that an attack would have dire consequences. Washington hopes Israeli leaders will give sanctions and other actions time to work against Iran first.

On Thursday, Obama spoke by telephone with Israeli Prime Minister Benjamin Netanyahu, while Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, will travel next week to Tel Aviv to meet Israeli defense officials, the paper said.

Efforts to contain Israeli actions come as Washington has warned Tehran against provocative actions such as attempting to close off the Strait of Hormuz in retaliation for a potential West-imposed oil embargo.

The exchange of diplomacy and warnings comes following the assassination of an Iranian nuclear scientist last week, which Tehran’s leaders have blamed on the U.S. Washington has denied involvement, but the car-bombing attack was only the latest in a series of what appear to be covert actions against Iranian nuclear and weapons infrastructure over the past year.

The actions, believed to be led by Israel, have been credited in slowing down the development of Iran’s alleged nuclear weapons program – a program Tehran denies. But Israeli officials have refused to rule out further actions if Tel Aviv deems them necessary.

“It is the policy of the Israeli government, and the Obama administration, that all options remain on the table. And it is crucial that the ayatollahs in Tehran take this policy seriously,” said Michael Oren, Israel’s ambassador to the U.S.