The United States is sending senior officials to Israel for a week of high diplomacy. There are wide gaps to be bridged.

Iran will top the agenda when American Secretary of Defense Robert Gates arrives in Israel on Monday. Gates is expected to urge Israel not to attack Iran's nuclear facilities, saying the planned U.S. dialogue with the Islamic Republic deserves time to bear fruit.

But Israel is skeptical. Zalman Shoval, a former Israeli ambassador to Washington, says Iran could use the dialogue to buy more time to build a nuclear bomb.

"What could happen is that the Iranians will go on in enriching uranium and reaching the stage where they can produce a bomb within a few weeks, or within a few months, and any controls or anything like that will be useless by then," he said.

Iran says its nuclear program is for peaceful purposes, but its President, Mahmoud Ahmadinejad, has threatened to wipe the Jewish state "off the map." Therefore, Israel has warned that if international diplomacy fails, it might launch a pre-emptive strike on Iran.

U.S. envoy George Mitchell will also visit Israel to discuss advancing the peace process with the Palestinians. He will press Israel to halt the expansion of Jewish settlements in the West Bank and disputed East Jerusalem.

So far, Israel has refused, creating a deepening rift with Washington. Israel says construction in West Bank settlements will continue to accommodate "natural growth," and that Jews can build anywhere in Jerusalem because it is the nation's capital.

"Obviously there are going to be matters on which there will be disagreement, including for instance building in Jerusalem, in the suburbs of Jerusalem, and about settlements," said Shoval.

Two other senior U.S. officials will visit Israel later in the week: National Security Adviser James Jones, and Middle East specialist Dennis Ross.