Israel has warned relentlessly against a nuclear deal with Iran but experts say Prime Minister Benjamin Netanyahu's options are limited and immediate military action is unlikely.
Ahead of Thursday's announcement in Lausanne on the framework of a potentially historic deal, Netanyahu had said any agreement needed to "significantly roll back Iran's nuclear capabilities".
And repeating previous Israeli warnings, Intelligence Minister Yuval Steinitz said all options were open.
"If we have no choice, we have no choice... the military option is on the table," he said.
Israel has been the loudest opponent of reaching a deal that would leave Iran with atomic capabilities, saying any potential for a nuclear-armed Tehran threatens the Jewish state's very existence.
But analysts said it was tough diplomacy -- not military strikes -- that would be the focus of Israeli efforts after Thursday's announcement, at least in the short term.
"After the entire world signed an agreement with Iran, I don't see Israel striking Iran nuclear facilities tomorrow morning," said Yoel Guzansky, the former head of the Iran desk at Israel's National Security Council.
"It will be seen as jeopardising global security," he said.
"However if the Iranians were caught cheating, then it's a different ball game, then you have the legitimacy to do other things."
Under the framework, nuclear-related US and EU sanctions against Iran will be lifted once the UN atomic watchdog has verified that Tehran has implemented its promises.
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.
Netanyahu should "keep the military option on the table. Not only the military option -- keep doing whatever is necessary to prevent Iran from having the nuclear capability," Kuperwasser said.
Discussion of an Israeli military attack on Iran's nuclear facilities peaked in 2011-2012, when Ehud Barak was defence minister and Netanyahu premier.
But Kuperwasser said talk of an attack does not necessarily translate into one.
"As long as you have a credible military option, the Iranians will be very careful to not put you in a position where you will have to use it," he said.
Emily Landau, an expert on nuclear strategy and arms control at the Institute for National Security Studies in Tel Aviv, said Israel is limited in what it can do in the face of what it considers to be a bad deal.
"It breaks down to attempts to convince" the world powers negotiating with Iran to reach a better agreement, she said.
"This is what it's been doing the whole time, and will continue doing with greater vigour," she said.
She said that despite the approach of a deal at the marathon talks in Switzerland, Netanyahu's statements have been less focused on military options.
"There is definitely a change in the nuance, the rhetoric has changed," she said.
"We no longer hear these insinuated threats of a military attack (on Iran's nuclear facilities) from Netanyahu," Landau said. "They mainly talk about their successes in convincing negotiators."
Some analysts warned Israel needs to stop looking at the Iranian issue in isolation.
Yehezkel Dror, a political science professor at the Hebrew University, said Israel was making "a severe mistake" in considering the peace process with the Palestinians and the Iranian issue as separate.
"If there will not be progress toward a peace accord that would look reasonable to the US and others -- and which would enable more cooperation with other anti-Iranian Arab states in the region -- our standings won't improve," he said.
The last round of Israeli-Palestinian peace talks broke down last year amid mutual recriminations, despite a strong push from Washington.
"Progress toward a peace agreement," even if it doesn't reach the final goal of an accord, "will also enable Israel to act, if the need arises, against Iran," Dror said.