Israeli Prime Minister Benjamin Netanyahu suffered a major defeat in failing to stop a nuclear deal with Iran but he remains as defiant as ever even at the risk of further isolation.

While the world's major powers welcomed the deal finalised with Iran on Tuesday as a historic moment capable of setting relations with the Islamic republic on a new path, Netanyahu harshly condemned it.

For the 65-year-old savvy rightwing prime minister, the agreement was a "stunning, historic mistake".

He stressed Israel would not be bound by the deal and -- again signalling that military force was not off the table -- said the country would "always defend ourselves".

On Wednesday, he declared the agreement was "not the end of the story".

"We are going to continue to denounce the danger in reaching an agreement with a dictatorial regime," he said.

Netanyahu argues the deal will fail to block Iran's path to nuclear weapons that could be used to target the Jewish state, and says the lifting of sanctions will allow it to further support proxy militants in the Middle East.

While he has angered US President Barack Obama by appearing before Congress in Washington to argue against the agreement, there is wide support for Netanyahu's stand among his political allies in Israel.

The opposition has also denounced the deal, while at the same time criticising Netanyahu for deteriorating relations with the United States, the country's most important ally.

"Netanyahu wants to go down in history as practically the only person to warn to the very end against the dangers of a nuclear Iran," a senior Israeli official told AFP on condition of anonymity.

"He knows in advance that it is a losing battle in the short-term, but he cannot stand idly by."

His focus now is likely to turn to the US Congress, which has 60 days to review the deal. Netanyahu has allies there, particularly among Republicans, but their chances of sinking the agreement appear unlikely for now.

Even if the deal is voted down in Congress, Obama can veto the move. Congress can only override the veto with a two-thirds vote.

Obama has sought to reassure Netanyahu, telling him in a telephone conversation on Tuesday night that the agreement was in Israel's "national security interest".

He also announced US Defence Secretary Ashton Carter would visit Israel next week.

British Foreign Secretary Philip Hammond said he was heading to Israel Wednesday night to explain the deal in person, with a meeting set with Netanyahu for Thursday.

- 'American umbrella'? -

Israel is believed to be the only country in the Middle East with atomic bombs, although it has never confirmed it.

The United States currently grants Israel some $3 billion (2.7 billion euros) in military aid yearly outside of spending on other projects, such as assistance in developing the country's Iron Dome missile defence system.

There has been talk of further assistance to compensate for Israel's concerns related to the deal, such as additional F-35 stealth fighters capable of evading Iranian detection. Israel has already ordered 33 F-35s.

Yuval Steinitz, the Israeli minister who has overseen the Iran dossier, however sought to keep the focus on the danger his country says the deal poses.

"We are very grateful for the assistance we get from the US," Steinitz said Wednesday.

"But I think it's wrong to use the word compensation because there is no real compensation for nuclear threat."

Akiva Eldar, a political analyst and columnist for the Al-Monitor website which covers the Middle East, said one strategy Israel may be seeking to pursue involves protection under an "American umbrella".

That would mean reaching an agreement specifying that any Iranian attack against Israel would be considered an attack against the United States, he said.

The Israeli official who spoke on condition of anonymity said discussions would also likely include further cooperation between US and Israeli intelligence to detect any potential violation of the nuclear agreement by Iran.

It is unclear whether Netanyahu, long known as a shrewd political operator, will continue to strongly criticise the deal in public but work more diplomatically behind the scenes.

Some in Israel have however begun to suggest it is time to move on.

"The nuclear deal in the making is far from perfect, but the skies are not going to fall on our head tomorrow," Yossi Melman, who focuses on security issues, wrote in The Jerusalem Post.

What happens next in Iran nuclear deal?
Vienna (AFP) July 15, 2015 - Following is a timeline for the implementation of a historic deal signed between Iran and six major powers on July 14 to curb Iran's nuclear programme in exchange for relief from sanctions.

The negotiators gave no specific dates for the implementation timeframe, other than saying it would begin "upon conclusion of the negotiations".

- July -

After announcing the deal, Iran and the P5+1 -- France, Britain, China, Russia, Germany and the United States -- said they would submit the so-called Joint Comprehensive Plan of Action to the United Nations Security Council for adoption "without delay".

The European Union is then expected to "promptly" endorse the resulting resolution.

EU foreign ministers will sign off on the agreement at a council meeting in Brussels on July 20.

Meanwhile, US President Barack Obama is set to submit the proposal to the US Congress for review by the end of this week.

- September -

The Republican-controlled US Congress then has 60 days, or until September, to give its verdict on the plan. This period is likely to be marked by high drama with intense lobbying on both sides.

Lawmakers have the option of passing a resolution preventing Obama from waiving most US sanctions.

The president can veto this - a move which in turn could be overridden if opponents can muster a two-thirds majority.

As a result, the total review period could last up to 82 days, stretching to early October.

Meanwhile, Iranian approval of the agreement should be more straightforward.

It will first have to be endorsed by the Supreme National Security Council, which reports to supreme leader Ayatollah Ali Khamenei.

The council includes two major architects of the nuclear deal -- President Hassan Rouhani and Foreign Minister Javad Zarif.

Parliament will then vote to approve the agreement. Parliamentary speaker Ali Larijani has said lawmakers will not stand in the way of a deal that has Khamenei's backing.

- November -

Iran's implementation of the deal will take about four months, or until November, according to Zarif.

- December -

The UN's atomic watchdog will issue a report on whether Iran has complied with nuclear-related measures. The report by the International Atomic Energy Agency (IAEA) is an essential verification step for international sanctions to be lifted.

- January 2016 -

If Iran has respected its engagements, the EU, UN and US will gradually begin to lift their sanctions.

- In five years -

A UN arms embargo on Iran will be lifted.

- In eight years -

If the IAEA determines that Iran's nuclear activities have stayed peaceful, the EU will terminate any remaining sanctions, while the US will end or modify any remaining sanctions.

- In 10 years -

When the 10-year limitations of the deal expire, Iran will be able to use the more modern centrifuge technology it insisted on being able to develop under the agreement. The UN Security Council "would no longer be seized of the Iran nuclear issue", or close the file.