Israeli Prime Minister Benjamin Netanyahu will lead talks with senior security officials following the striking of a framework nuclear deal between Iran and world powers.
Local media reported that Netanyahu had called a meeting of his security cabinet, including ministers, as well as senior officials from Israel's security services on Friday.
The outline agreement aimed at curbing Iran's nuclear drive was clinched on Thursday after marathon talks in Switzerland, and marks a major breakthrough in a 12-year standoff between Iran and western countries, which have long announced a concern that Tehran wants to build an atomic bomb.
Reading out a joint statement on Thursday evening, EU foreign policy chief Federica Mogherini said a "decisive step" has been achieved.
"This is a crucial decision laying the agreed basis for the final text of joint comprehensive plan of action. We can now start drafting the text and annexes," said Mogherini, who has acted as a coordinator for the six powers - Britain, China, France, Germany, Russia and the United States.
Iranian Foreign Minister Mohammad Javad Zarif called it a "win-win outcome", while US President Barack Obama hailed the deal as a moment that the US and its allies had "reached a historic understanding with Iran".
But Al Jazeera's James Bays, reporting from Lausanne where the deal was struck, said that US diplomats still faced the challenge of convincing opposition Republican dissenters in Congress, and its ally Israel that the deal was sufficient.
Israel responds
Israel has argued relentlessly against such a deal and Netanyahu said on Thursday that an agreement would have to "significantly roll back Iran's nuclear capabilities".
In a phone conversation with Obama, Netanyahu said that a final deal based on this agreement "would threaten the survival of Israel", while the prime minister's spokesperson Mark Regev quoted the premier as saying that the emerging deal "would not block Iran's path to the bomb. It would pave it".
But Obama said that the issues at stake are "bigger than politics".
"These are matters of war and peace," he said, and if the Republican party-controlled Congress kills the agreement "international unity will collapse, and the path to conflict will widen".
Iranians celebrate the nuclear agreement with world powers in Lausanne, on a street in northern Tehran [AP]
Netanyahu echoes Obama's concern but conversely. "[The emerging deal] would increase the risks of nuclear proliferation and the risks of a horrific war," Regev quoted him as saying.
Repeating previous Israeli warnings, Intelligence Minister Yuval Steinitz said on Thursday that all options were open. "If we have no choice, we have no choice... the military option is on the table," he said.
Israel is the Middle East's sole, albeit unacknowledged, nuclear power.
Yossi Kuperwasser, until recently the director general of Israel's strategic affairs ministry, said Netanyahu would be seeking to keep up pressure right up until a final accord, which is due to be drafted by the end of June, AFP news agency reported.

Al Jazeera's Patty Culhane explains Obama's take
He's keeping sanctions in regard to human rights violations and funding of groups the US considers to be terrorists. The critics have said easing sanctions will give Iran more money to fund groups like Hezbollah.
The biggest complaint from critics is that this only limits Iran for 10-15 years. The president made sure to say in his speech that Iran is a signatory to the NPT so that means they will never get a nuclear bomb.
The president has the public on his side. Polls show the majority of Americans want a diplomatic solution. He is going to fight Congress by making the case to the American people if they vote down the deal they are voting for war.
The deal will limit Iran's nuclear activity to the Natanz plant and reduce the number of centrifuges it operates from 19,000 today to just over 6,104.
Iran has also agreed to not build any new facilities for the purpose of enriching uranium for 15 years.
Zarif said the countries had agreed on  an elaborate mechanism if any of the parties to the agreement "returned to old practises" and reneged on their obligations.
"We will not allow excuses that will allow a return to the old system," Zarif said.
Mogherini said the seven nations would now start writing the text of a final accord.
She cited several agreed-upon restrictions on Iran's enrichment of material that can be used either for energy production or in nuclear warheads. She said Iran will not produce weapons-grade plutonium.
Sanctions related to Iran's nuclear programmes would be suspended by the US, the United Nations and the European Union after the International Atomic Energy Agency has confirmed Iran's compliance.