JERUSALEM - Israel's prime minister harshly condemned the international community's nuclear deal with Iran on Sunday while Saudi Arabia remained conspicuously quiet, reflecting the jitters felt throughout the Middle East over Iran's acceptance on the global stage.
Elsewhere, many welcomed the agreement as an important first step toward curbing Iran's suspect nuclear program.
Israel and Western-allied Gulf countries led by Saudi Arabia have formed an unlikely alliance in their opposition to Sunday's deal, joined together by shared concerns about a nuclear-armed Iran and the Tehran's growing regional influence.
Iranian President Hassan Rouhani speaks during a press conference Sunday after Iran and world powers agree in Geneva to a deal over Iran’s nuclear program in Tehran.
While most Gulf countries remained silent in the first hours after the deal was reached in Geneva, Israeli Prime Minister Benjamin Netanyahu wasted little time in criticizing it, calling it a "historic mistake" and saying he was not bound by the agreement.
Speaking to his Cabinet, Netanyahu said the world had become a "more dangerous place" as a result of the deal. He reiterated a long-standing threat to use military action against Iran if needed, declaring that Israel "has the right and the duty to defend itself by itself."
Sunday's agreement is just the first stage of what is hoped to bring about a final deal ensuring that Iran does not develop a nuclear weapon.
Under the deal, Iran will curb many of its nuclear activities for six months in exchange for limited and gradual relief from painful economic sanctions. The six-month period will give diplomats time to negotiate a more sweeping agreement.
The package includes freezing Iran's ability to enrich uranium at a maximum 5 percent level, which is well below the threshold for weapons-grade material and is aimed at easing Western concerns that Tehran could one day seek nuclear arms. International monitors will oversee Iran's compliance.
For Iran, keeping the enrichment program active was a critical goal. Iran's leaders view the country's ability to make nuclear fuel as a source of national pride and an essential part of nuclear self-sufficiency.
But Israel views any enrichment as unacceptable, saying making low-level enriched uranium weapons grade is relatively simple. It demands all enrichment be halted, and that Iran's abilities to produce uranium be rolled back.
Netanyahu had also called for economic sanctions to be increased. Israel fears that Iran will use the diplomatic process as cover to trick the international community, much the way North Korea did in its march toward a nuclear bomb.
"Today the world became a much more dangerous place," Netanyahu said.
The White House said President Barack Obama had phoned Netanyahu to discuss the tentative deal with Iran, with the two leaders reaffirming "their shared goal of preventing Iran from obtaining a nuclear weapon."
Obama told Netanyahu that he understands Israel "has good reason to be skeptical about Iran's intentions," but promised to "consult closely" with its ally regarding efforts to negotiate a comprehensive solution that would "resolve the international community's concerns regarding Iran's nuclear program," according to a statement released by the office of the White House press secretary.
Israeli officials acknowledged they would have to turn their focus toward affecting the outcome of the final negotiations. Israel is not part of the Geneva talks but remains in close touch with the U.S. and other participants.
Israel feels especially threatened by Iran, given Tehran's repeated references to destroying Israel, its support for hostile militant groups on Israel's borders and its development of long-range missiles.
Israeli President Shimon Peres, a Nobel Peace laureate, expressed cautious optimism that Sunday's deal could change the region.
"I would like to say to the Iranian people: You are not our enemies and we are not yours. There is a possibility to solve this issue diplomatically. It is in your hands. Reject terrorism. Stop the nuclear program. Stop the development of long-range missiles," he said.
Another Nobel peace laureate, Mohammed ElBaradei, Egypt's pro-democracy leader and former director of the United Nations nuclear watchdog agency, welcomed the deal.
In a tweet on his official account, he wrote: "After decade of failed policies, world better off w/ Iran deal. Equity, trust building, respect & dialogue R key to any conflict resolution."
The muted response in the Gulf came after the rulers of Qatar and Kuwait met Saudi King Abdullah over the weekend to discuss regional issues, foremost Iran.
Saudi Arabia and Iran's regional enmity increasingly has played out as a proxy war in Syria with both countries providing lethal support for the warring sides. Saudi Arabia also accuses Iran of backing Shiite unrest across the region.
Bucking the trend, the tiny Gulf countries of Bahrain and the United Arab Emirates praised the agreement.
Hamas called the deal a sign of Iran's rising power and prominence.