Iran and the United States are set to hold discussions in Oman on Saturday to revive negotiations concerning Tehran’s advancing nuclear program. However, even before the talks begin, there’s a disagreement over the format of the negotiations.

US President Donald Trump claims there will be direct talks, while Iran’s foreign minister asserts they will be conducted indirectly through a mediator.

In a post on X, Iran’s foreign minister Seyed Abbas Araghchi said, “Iran and the United States will meet in Oman on Saturday for indirect high-level talks. It is as much an opportunity as it is a test. The ball is in America’s court.”

Although the distinction between direct and indirect talks may seem minor, it holds significant weight. Indirect negotiations have made little headway since President Trump unilaterally withdrew the US from the 2018 nuclear deal with world powers during his first term.

Trump has escalated tensions by imposing new sanctions on Iran as part of his “maximum pressure” strategy. He has also hinted at the possibility of military action against Iran, while expressing optimism about reaching a new deal through diplomatic means, including writing a letter to Iran’s 85-year-old Supreme Leader, Ayatollah Ali Khamenei.

In response, Khamenei has warned that Iran would retaliate against any attack with its own counterstrike.

Here’s what you need to know about the letter, Iran’s nuclear program, and the longstanding tensions that have shaped relations between Tehran and Washington since the 1979 Islamic Revolution.

Since returning to the White House, President Trump has been advocating for negotiations while simultaneously increasing sanctions and suggesting that a military strike by either Israel or the US could target Iran’s nuclear facilities.

During his first term, a letter from Trump to Iran’s Supreme Leader provoked a strong and angry response.

In contrast, Trump’s letters to North Korean leader Kim Jong Un during his first term led to face-to-face meetings, though these talks did not result in any agreements to curb Pyongyang’s nuclear arsenal or its missile program capable of reaching the continental US.

“We don’t avoid talks; it’s the breach of promises that has caused issues for us so far,” Pezeshkian said in televised remarks during a Cabinet meeting. “They must prove that they can build trust.”

Khamenei seemingly reacted to comments by Trump, renewing his threat of military action.

“They threaten to commit acts of mischief, but we are not entirely certain that such actions will take place,” the supreme leader said. “We do not consider it highly likely that trouble will come from the outside. However, if it does, they will undoubtedly face a strong retaliatory strike.”

Iranian Foreign Ministry spokesperson Esmail Baghaei went further.

“An open threat of ‘bombing’ by a Head of State against Iran is a shocking affront to the very essence of International Peace and Security,” he wrote on the social platform X. “Violence breeds violence, peace begets peace. The US can choose the course…; and concede to CONSEQUENCES.”

The state-owned Tehran Times newspaper, without citing a source, claimed that Iran had “readied missiles with the capability to strike U.S.-related positions.” That’s as the U.S. has stationed stealth B-2 bombers in Diego Garcia within striking distance of both Iran and Yemen’s Iranian-backed Houthi rebels, which America has been bombing intensely since March 15.

Under the terms of the 2015 nuclear deal, Iran was permitted to enrich uranium up to 3.67% purity and to hold a uranium stockpile of 300 kilograms (661 pounds). According to the latest report from the International Atomic Energy Agency, Iran’s stockpile has grown to 8,294.4 kilograms (18,286 pounds), with a portion of it enriched to 60% purity.

U.S. intelligence agencies assess that Iran has yet to begin a weapons program, but has “undertaken activities that better position it to produce a nuclear device, if it chooses to do so.”

Ali Larijani, an adviser to Iran’s supreme leader, has warned in a televised interview that his country has the capability to build nuclear weapons, but it is not pursuing it and has no problem with the International Atomic Energy Agency’s inspections. However, he said if the U.S. or Israel were to attack Iran over the issue, the country would have no choice but to move toward nuclear weapon development, as reported by Associated Press.

“If you make a mistake regarding Iran’s nuclear issue, you will force Iran to take that path, because it must defend itself,” he said.

In January 1979, the shah of Iran, gravely ill with cancer, fled the country amid growing mass protests against his regime. This led to the Islamic Revolution, spearheaded by Grand Ayatollah Ruhollah Khomeini, establishing Iran’s theocratic government.

Later that same year, Iranian university students stormed the U.S. Embassy in Tehran, demanding the extradition of the shah. This incident triggered the 444-day hostage crisis, which resulted in the severance of diplomatic ties between Iran and the U.S. During the 1980s Iran-Iraq war, the U.S. supported Saddam Hussein, and in the so-called “Tanker War,” launched a one-day naval assault that significantly damaged Iran’s maritime capabilities. The U.S. also shot down an Iranian commercial airliner during this period.

Since then, U.S.-Iran relations have fluctuated between hostility and cautious diplomacy. Relations briefly improved with the 2015 nuclear deal between Iran and world powers, but tensions resurged after President Trump unilaterally pulled the U.S. out of the agreement, fueling ongoing conflicts in the Middle East.

Bessent stated that the Trump administration is exerting maximum economic pressure to disrupt Iran’s financial networks, which support Hamas and other militant groups across the Middle East, as well as Iran’s nuclear ambitions.

In March, the US Treasury imposed sanctions on tankers transporting Iranian oil and on a Chinese “teapot” refinery for processing the crude. “Teapots” are small, independent refineries in China, and China’s national oil company refineries have ceased purchasing Iranian oil due to sanction-related risks.