Why Israel and Iran are enemies: the history from 1948 to 2026

In 1979, a few days after the Islamic Revolution, Israel's embassy in Tehran was closed and handed over to the Palestine Liberation Organization, the PLO. It was the end of almost three decades of quiet partnership between the two countries.

Today, Israel and Iran are at war. To understand how they got here, you have to go back to the time when they were friends.

An old relationship

The link between Jews and Persians is more than 2,500 years old. In 539 BC, the Persian king Cyrus the Great conquered Babylon and allowed exiled Jews to return to Jerusalem. He appears in the Bible as a liberator.

Jews have lived in what is now Iran ever since. Even after 1979, the country kept the largest Jewish community in the Middle East outside Israel, with a guaranteed seat in parliament.

The quiet allies

When Israel was founded in 1948, Iran was ruled by Shah Mohammad Reza Pahlavi, a monarch aligned with the United States. In 1950, Iran became one of the first Muslim-majority countries to recognize Israel in practice, without opening an official embassy.

The two had common enemies: the Arab nationalism of Gamal Abdel Nasser's Egypt and Soviet influence in the region. Israel bought Iranian oil, Israeli companies worked in Iran, and the intelligence services cooperated.

1979: the ideological enemy

The Islamic Revolution toppled the shah in 1979 and brought Ayatollah Ruhollah Khomeini to power. The new regime defined itself against the United States, called the "Great Satan," and against Israel, which it stopped recognizing as a state.

For Khomeini, the Palestinian cause was also a way to lead the Muslim world, even though Iran is Shia and Persian, not Arab.

Even so, pragmatism lasted a few years. During the war with Iraq, from 1980 to 1988, Israel sold weapons to Iran, because it saw Saddam Hussein as the bigger threat. Some of those sales surfaced in the Iran-Contra affair in the United States.

Hezbollah and the proxy war

In 1982, Israel invaded Lebanon. In the same period, Iran's Revolutionary Guard helped create Hezbollah, a Lebanese Shia militia and party that became Iran's main armed arm on Israel's northern border.

Over the years, Iran built what it calls the "axis of resistance": Hezbollah, Palestinian groups such as Hamas and Islamic Jihad, militias in Iraq and Syria and, later, Yemen's Houthis.

South America is part of this story too. Argentina accuses Iran and Hezbollah of the bombings of Israel's embassy in Buenos Aires in 1992 and of the AMIA Jewish center in 1994, which killed 85 people. Iran denies it.

The bomb that does not exist

Since 2002, when the Natanz uranium enrichment plant was revealed, the nuclear program has been at the center of the rivalry. Iran says it is peaceful. Israel, which neither confirms nor denies having nuclear weapons, considers a nuclear-armed Iran a threat to its existence.

A shadow war followed. Around 2010, the Stuxnet computer virus damaged centrifuges at Natanz, in an operation attributed to the United States and Israel. Iranian nuclear scientists were assassinated.

In 2015, the nuclear deal between Iran and the major powers limited enrichment in exchange for sanctions relief. In 2018, Donald Trump's administration pulled the United States out of the deal, and Iran sped up its program again.

From the shadows to open war

After Hamas's attack on Israel on October 7, 2023, and the war in Gaza, the rivalry came out of the shadows. In April 2024, after an Israeli strike on the Iranian consulate in Damascus, Iran attacked Israel directly for the first time, with hundreds of drones and missiles.

In June 2025, the two countries fought the so-called Twelve-Day War, in which the United States bombed Iranian nuclear facilities.

On February 28, 2026, the United States and Israel launched a new war against Iran. The strikes killed Supreme Leader Ali Khamenei, who was succeeded by his son, Mojtaba Khamenei. Iran responded with missiles against Israel and US bases and closed the Strait of Hormuz. Since then, ceasefires and deals have been announced and have fallen apart.

Why does this matter for Brazil?

Brazil has relations with both countries. In 2010, Brazil and Turkey negotiated the Tehran Declaration with Iran, a proposal to swap Iranian uranium for nuclear fuel, which the major powers ended up ignoring.

Today, the most direct effect of the rivalry reaches people's wallets: the war closed Hormuz and drove up oil and fertilizer prices. Read more in why the Strait of Hormuz moves diesel prices in Brazil.

Quick questions

Were Israel and Iran ever allies?

Yes. From 1950 to 1979, under the shah, the two kept a quiet partnership in oil, trade and intelligence.

Why did Iran break with Israel?

The 1979 Islamic Revolution brought to power a regime that does not recognize Israel and adopted the Palestinian cause as a banner.

What role does the nuclear program play?

Israel considers a nuclear-armed Iran a threat to its existence. Iran says the program is peaceful.

Are Israel and Iran at war?

Yes. After direct attacks in 2024 and the June 2025 war, the United States and Israel began a new war against Iran on February 28, 2026.

Sources

Found an error? See how we fact-check and correct.

Why Israel and Iran became enemies after being allies