By Dan Williams and Luke Baker
JERUSALEM (Reuters) - Israel will ramp up its lobbying of the U.S. Congress to try to hinder the nuclear agreement struck with Iran on Tuesday and minutely monitor the deal for any violations in the hope of getting sanctions reimposed on Tehran.
Responding with alacrity to news that six world powers had agreed to lift sanctions on Iran in exchange for curbs on its nuclear program, Israel's prime minister and other senior officials condemned the historic pact.
Prime Minister Benjamin Netanyahu, who has described Iran as akin to the militants of Islamic State, said the deal was "a stunning, historic mistake".
In a statement before convening his inner circle of ministers to discuss the deal, he added: "Israel is not bound by this deal with Iran because Iran continues to seek our destruction. We will always defend ourselves."
The ministers, referred to as the Security Cabinet, later rejected the deal unanimously, the prime minister's office said in a statement which echoed Netanyahu's own words.
In another speech after the end of the Security Cabinet meeting, Netanyahu spoke in Hebrew in an address aimed at a domestic audience.
"Now we have one objective: To ensure that (Iran) won't arm itself in the future with nuclear weapons ... This is the time to unite and form a single front in a fateful matter for Israel's future," he said.
He also held a phone conversation with U.S. President Barack Obama in which he expressed Israel's concern over the deal, an Israeli government source said.
"It will afford Iran the ability to arm itself with nuclear weapons in 10-15 years' time, whether it keeps to the agreement, and beforehand if it breaks the deal," the source said.
"Additionally, it will channel billions of dollars to the Iranian terror and war machine which threatens Israel and the entire world."
In the call, Obama underscored the United States' commitment to Israel's security, the White House said.
Iran does not recognize Israel and has in the past said it should be wiped off the map, leading the small Jewish state, widely assumed to possess the Middle East's only nuclear arsenal, to portray Iran as a threat to its existence.
Having spent months trying to stall the deal and expose its perceived frailties, Israeli officials said they would now focus on persuading the U.S. Congress to reject it, while tracking Iran meticulously to catch violations.
In an indication of the broad opposition to the deal in Israel, center-left leader Isaac Herzog, Netanyahu's chief political rival, said he would soon visit the United States to lobby for more U.S. military support as a defense against Iran.
U.S. lawmakers have 60 days to review the deal, with Obama seeking bipartisan support for an agreement that would be a central plank of his legacy. Even if the review goes against Obama, he could overrule Congress by veto, although that would tarnish the achievement.
"HOLES IN THE AGREEMENT"
"Israel must focus and explain all of the holes in this agreement, which will just intensify terrorism and increase Middle East chaos," Gilad Erdan, minister of public security and a member of Netanyahu's Likud party, told Israel's Army Radio.
Netanyahu's relations with the White House are already rocky, not least because he addressed a joint session of Congress in March to criticize the emerging deal, and some in Israel have questioned the value of lobbying Congress again.
But confidants of Netanyahu said he was as determined as ever to have his views heard.
"Why shouldn't we go all-out in Congress?" one person close to Netanyahu said. "Even if we don't garner all the votes we need, and even if Obama exercises a presidential veto to get the Iran deal ratified, it will still have symbolic value for us."
Dore Gold, director-general of Israel's Foreign Ministry and a veteran Netanyahu adviser, saw no need to "feel ashamed" about arguing against the nuclear deal in the United States - which he insisted could be done without aggravating Obama personally.
Gold said open communications were needed to report and act on any attempt by Iran to violate the curbs on its nuclear program, an allusion to increased Israeli monitoring.
Under the agreement, international sanctions on Iran could be reimposed within 65 days if Tehran violates any part of the pact, diplomats said.
Netanyahu has also beefed up Israel's armed forces, which have been tasked with preparing last-ditch strikes on Tehran's nuclear sites - though such a prospect has little support domestically and is seen as highly unlikely.
Erdan said war had not been ruled out: "Israel is keeping all options on the table, diplomatic or otherwise."
Washington, which gives Israel $3 billion in annual defense grants and has signaled that it is open to increasing that, has tried to stay its ally's hand with joint missile defense projects designed to offset the threat from Iran.
At the same time, the United States has increased defense support to other allies in the region who have concerns about Iran, including Saudi Arabia, Jordan, Egypt and the Gulf states.
(Additional reporting by Maayan Lubell, Ori Lewis and Ali Sawafta; Writing by Dan Williams; Editing by Kevin Liffey and Giles Elgood)