America's top general sought to reassure Israel on Tuesday of "unshakable" U.S. military support, despite deep strains in political relations over the prospect of a U.S.-led nuclear deal with Iran and differences over Israeli-Palestinian diplomacy.

U.S. General Martin Dempsey, on a visit to Israel, said he shared a core Israeli fear that sanctions relief for Iran following a nuclear agreement would allow Tehran to give more money to its military and its guerrilla proxies.

"My assessment is that I share their concern. If the deal is reached and results in sanctions relief ... it's my expectation that it's not all going to flow into their economy," he said.

"I think that they will invest in their surrogates. I think they will invest in additional military capability," Dempsey, the chairman of the Joint Chiefs of Staff, told a small group of reporters in Jerusalem.

But Dempsey said the long-term prospects were "far better" with an Iran that was not a nuclear weapons power. He reassured Israeli defense officials that Washington would work to mitigate Iran-related risks, with or without a deal.

"That's what my visit here has been about, reassuring them that we're clear-eyed about the risks that Iran poses to the region and we will work with our partners to address those risks," Dempsey said.

Israeli Prime Minister Benjamin Netanyahu has presented the planned nuclear deal as a threat to Israel. U.S. President Barack Obama, addressing Israeli television last week, renewed his assertion that a deal would do a better job than air strikes in preventing Iran from becoming a nuclear weapons power, an ambition Iran denies.

As the end-June deadline for an Iran nuclear deal approaches, Dempsey said the United States and Israel had to be prepared for either success or failure in the talks.

"If a deal is made, we've got work to do. If a deal is not made, we've got work to do," Dempsey said, hinting that the U.S. military might eventually need to address the threat from Iran's nuclear program if diplomatic efforts fail.

"And I think we've built up enough trust and confidence in each other � military to military � that we're prepared to do that work."

The prospect of an increasingly assertive Iran has also unnerved Gulf states, which have in turn sought to build up their militaries, including with U.S. weaponry. Obama hosted leaders of the Sunni Arab states last month in the U.S.

Israeli Defense Minister Moshe Yaalon voiced concern on Tuesday that Washington's supply of advanced arms to Gulf Arab states to deter Iran could eventually challenge Israel's U.S.-backed regional military supremacy, if not addressed.

"Even if there are not now any hostile designs (among them) against us, as we know in the Middle East intentions are liable to change. The capability will without a doubt be there and this must be prepared for," he said.

Dempsey, in a nod to the possibility of greater U.S. defense assistance in the years ahead, said he discussed those concerns.

"Israel wants not only to overmatch them in technology, but they realize that there�s a size component to this as well," Dempsey said.

He singled out discussions about future support to "thicken" Israel's integrated air and missile defense system, its cyber defenses, maritime security and explore counter-tunneling defenses.

By Reuters