By Phil Stewart
HUSSEIN LOOKOUT, Israel (Reuters) - As U.S. Defense Secretary Ash Carter walked along an Israeli lookout near the border with Lebanon, Israel's Defence Minister Moshe Yaalon turned to him and said: "Probably Hezbollah is watching us."
Israel warned during Carter's visit on Monday it feared a deal on curbing Iran's nuclear programme in return for sanctions relief would translate into more money for Hezbollah, an Iranian-backed Lebanese militia group, and others hostile to Israel.
Carter, standing at the Hussein Lookout, not far from the northern Israeli border town of Manara, promised to help, trying to reassure Israel of steadfast U.S. support following last week's deal between Tehran and six world powers.
"Hezbollah is sponsored, of course, by Iran which is one of the reasons why the United States will continue to help Israel counter Iranian malign influence in this region," Carter told reporters travelling with him.
Washington and Israel are split over the Iranian nuclear deal, with President Barack Obama saying it makes the United States and its allies safer. Israeli Prime Minister Benjamin Netanyahu says it does not.
On Sunday, Netanyahu urged U.S. lawmakers to reject a deal he said would only feed an "Iranian terror machine".
Israel is widely believed to have the only nuclear arsenal in the Middle East.
Hezbollah, which fought the Israeli armed forces to a standstill in their 2006 war, has since expanded its arsenal and honed its skills helping Damascus to fight rebels in Syria.
Yaalon was careful not to criticize Carter, who he at one point called "my dear friend, Ash". But he acknowledged the disagreement and outlined some of the dangers he saw ahead, including from the Palestinian group Hamas which runs Gaza.
"No doubt the proxies around us, like Hezbollah, Hamas ... we believe they are going to get more money," Yaalon told a news conference in Tel Aviv, standing alongside Carter.
Iranian Supreme Leader Ayatollah Ali Khamenei said over the weekend that the nuclear deal would not change Tehran's policy in supporting allies including in Lebanon, Syria and among the Palestinians.
But Carter has repeatedly stressed that although the nuclear deal placed limits on Iran, it would not prevent the United States from bolstering its allies in the region.
Israel believes Hezbollah has more than 100,000 missiles capable of paralysing its civilian infrastructure. Seeking to deter the guerrillas, Israeli generals have threatened to devastate Lebanon should there be another full-on conflict.
Both Yaalon and Carter acknowledged the risks from the unravelling of Syria, just to the east of the Hussein Lookout.
"The nations surrounding us are falling apart," Yaalon lamented. Carter said the United States was "planning for various scenarios" in Syria.
(Additional reporting by Dan Williams in Tel Aviv; editing by David Stamp)