US-Iran Peace Deal Ends 3.5-Month War: A Detailed Timeline of the Decades-Long Nuclear Standoff and Middle East Conflict
Washington/Tehran: In a major geopolitical breakthrough, the United States and Iran on Sunday agreed to end the three-and-a-half-month conflict that had destabilized the Middle East and disrupted global trade routes.
The agreement is expected to restore maritime traffic through the strategically vital Strait of Hormuz, easing concerns over global energy supplies and international shipping.
Confirming the development, US President Donald Trump announced that Washington would lift its naval blockade around Iranian ports, a move widely seen as the most significant diplomatic achievement in months of tense negotiations between the two countries.
The agreement marks the latest chapter in a confrontation that has its roots in decades of mistrust, nuclear disputes, sanctions, and regional conflicts.
1967–2012: The Origins of Iran’s Nuclear Programme and Growing Tensions
1967: Nuclear Programme Begins with US Support
Iran’s nuclear programme traces its origins to 1967, when the United States supplied the Tehran Research Reactor under President Dwight Eisenhower’s “Atoms for Peace” initiative.
At the time, Washington viewed Iran as a close ally and supported the development of peaceful nuclear technology in the country.
1979: Islamic Revolution Changes US-Iran Relations
The political landscape shifted dramatically in 1979. Amid widespread anti-government protests, Shah Mohammad Reza Pahlavi, a key US ally who was seriously ill, fled Iran.
His departure paved the way for the return of Ayatollah Ruhollah Khomeini, whose arrival ushered in the Islamic Revolution and transformed Iran into an Islamic Republic.
Relations between Tehran and Washington deteriorated sharply after revolutionary students seized the US Embassy in Tehran, triggering the infamous 444-day hostage crisis.
The episode fundamentally altered US-Iran relations and temporarily halted progress on Iran’s nuclear ambitions.
2002–2003: Secret Nuclear Facilities Exposed
International scrutiny intensified in 2002 and 2003, when intelligence agencies revealed the existence of Iran’s previously undisclosed Natanz uranium enrichment facility.
The discovery sparked global concern and prompted Britain, France, and Germany to initiate diplomatic negotiations with Tehran.
Facing growing international pressure, Iran agreed to suspend uranium enrichment activities while talks continued.
2006: Nuclear Negotiations Collapse
The election of hardline president Mahmoud Ahmadinejad in 2005 led to a significant shift in Iran’s nuclear policy. In 2006, Tehran announced that it would resume uranium enrichment.
The decision effectively derailed negotiations with European powers, prompting Britain, France, and Germany to abandon stalled diplomatic discussions.
2009–2012: Protests, Crackdowns, and Secret Diplomacy
Following Ahmadinejad’s controversial re-election in 2009, allegations of electoral fraud triggered mass demonstrations known as the Green Movement.
The protests were met with a harsh crackdown by Iranian authorities, resulting in widespread arrests and international criticism.
Despite escalating tensions, diplomatic contacts quietly resumed behind the scenes.
Later that year, the United States and Iran established a secret communication channel through Oman, facilitating indirect exchanges.
By 2012, officials from the administration of US President Barack Obama were holding confidential discussions with Iranian representatives in the Gulf nation.
2015–2018: The Rise and Collapse of the Nuclear Deal
2015: The Joint Comprehensive Plan of Action
After years of negotiations, Iran and major world powers reached a landmark agreement in 2015 known as the Joint Comprehensive Plan of Action (JCPOA).
The accord imposed strict limits on Iran’s nuclear programme, particularly uranium enrichment activities, in exchange for relief from international economic sanctions.
The agreement was widely hailed as a diplomatic success aimed at preventing Iran from developing nuclear weapons.
2018: Trump Withdraws from the Agreement
The future of the deal changed dramatically in 2018 when President Donald Trump withdrew the United States from the JCPOA, describing it as the “worst deal ever.”
Trump argued that the agreement failed to address Iran’s ballistic missile programme and its support for armed groups across the Middle East.
He pledged to negotiate a stronger and more comprehensive deal, although no breakthrough was achieved during his first term in office.
2019: Iran Begins Scaling Back Commitments
In response to renewed sanctions and Washington’s withdrawal from the agreement, Iran announced in 2019 that it would gradually reduce its compliance with the nuclear accord.
The period that followed witnessed a series of attacks on land targets and commercial vessels across the region. Many of these incidents were attributed by Western governments and regional rivals to Iran, further heightening tensions.
2020–2021: Escalation and Nuclear Advancements
2020: Soleimani Assassination and Rising Conflict
One of the most consequential moments in recent Middle Eastern history occurred in January 2020, when Iranian military commander General Qassem Soleimani was killed in a US drone strike.
Often regarded as the architect of Iran’s regional military strategy, Soleimani’s death prompted swift retaliation.
Iran launched missile attacks on military bases in Iraq hosting US forces, causing traumatic brain injuries to more than 100 American personnel, according to the Pentagon.
In another tragic development, Iran’s Revolutionary Guard mistakenly shot down a Ukrainian passenger aircraft after reportedly identifying it as a hostile missile threat. All 176 people on board lost their lives.
Later that year, an explosion at Iran’s Natanz nuclear facility, widely blamed on Israel, destroyed a centrifuge production plant and further intensified the shadow conflict between the two countries.
2021: Renewed Negotiations and Higher Enrichment Levels
In 2021, Iran and the administration of US President Joe Biden began indirect negotiations in Vienna aimed at reviving the nuclear agreement.
However, progress remained fragile. During the same year, the Natanz facility suffered another attack attributed to Israel.
In response, Tehran significantly accelerated its nuclear activities, enriching uranium to 60 percent purity by April 2021—just short of the level generally associated with weapons-grade material.
2023–2024: Proxy Wars and Regional Confrontation
2023: Hamas Attack Sparks Regional Crisis
Regional tensions surged in October 2023, when Hamas militants launched a large-scale attack on Israel from Gaza, killing approximately 1,200 people and taking 251 hostages.
Iran was accused by Israel and its allies of supporting Hamas, leading to a sharp escalation in hostilities across the region.
2024: Direct Military Exchanges Between Iran and Israel
The confrontation entered a new phase in 2024 when Iran launched direct missile and drone strikes against Israel in April and October.
Israel responded by targeting Iranian air defence systems and military infrastructure.
The conflict further intensified with the assassinations of several prominent figures allied with Tehran, including Hamas political leader Ismail Haniyeh, reportedly killed in Tehran, and Hezbollah chief Hassan Nasrallah in Lebanon.
2025: Diplomacy, Sanctions, and the Road to War
Trump Returns to Office
Following his return to the White House in January 2025, President Trump sought to reopen direct diplomatic engagement with Tehran.
Despite five rounds of negotiations held in Oman and Rome, discussions repeatedly stalled, preventing a comprehensive breakthrough.
Nuclear Dispute Deepens
The International Atomic Energy Agency (IAEA) concluded that Iran was not complying with certain nuclear obligations. Tehran responded by activating a third uranium enrichment site, further escalating concerns.
Shortly thereafter, Israel launched military operations against Iran. The United States joined the campaign and conducted strikes on three Iranian nuclear facilities.
The confrontation eventually culminated in a ceasefire brokered by President Trump.
Sanctions Return and Domestic Unrest Grows
The diplomatic environment deteriorated further when Britain, France, and Germany initiated a process to restore pre-2015 United Nations sanctions against Iran through a mechanism commonly referred to as “snapback” sanctions.
The renewed restrictions severely affected Iran’s economy. By December 2025, the Iranian rial had reportedly fallen to a historic low of 1.42 million rials per US dollar.
As economic conditions worsened, widespread protests erupted across the country. Iranian authorities responded with a severe crackdown, including internet shutdowns and extensive security operations.
2026: Leadership Change, Regional War, and Peace Agreement
February 2026: War Erupts
On February 28, 2026, the conflict escalated dramatically when the United States and Israel jointly launched a large-scale military campaign against Iran.
During the war, Iran’s Supreme Leader Ayatollah Ali Khamenei was killed. His son, Mojtaba Khamenei, subsequently emerged as the country’s new ruler.
The fighting triggered the temporary closure of the Strait of Hormuz, one of the world’s most important maritime chokepoints, causing major disruptions to global energy markets and shipping networks.
April 2026: Fragile Ceasefire Emerges
In an effort to halt the conflict, a US delegation led by Vice President JD Vance met Iranian leaders in Pakistan in April 2026.
The talks resulted in a fragile ceasefire that temporarily reduced hostilities. President Trump later extended the ceasefire indefinitely while simultaneously warning Iran that failure to reach a satisfactory agreement could result in devastating consequences.
June 2026: Fighting Resumes Before Breakthrough Agreement
Despite diplomatic efforts, the ceasefire collapsed in June as Iran, Israel, and the United States exchanged fresh rounds of military strikes.
However, negotiations continued behind the scenes, eventually producing an initial breakthrough agreement aimed at ending the war and reopening the Strait of Hormuz to international shipping.
The agreement announced on Sunday represents the culmination of decades of confrontation, failed negotiations, sanctions, proxy conflicts, and military escalation.
While significant challenges remain, the deal has raised hopes that one of the world’s most enduring geopolitical disputes may finally be moving toward a more stable and peaceful phase.
— With inputs from AP
