Lebanon emerges as biggest obstacle to Iran-US nuclear negotiations

Fast-moving negotiations between the United States and Iran over ending the war have hit a fresh impasse, as Israel's expanding offensive against Iran-backed Hezbollah in Lebanon has thrust the Lebanese front to the center of the diplomatic standoff.

The core sticking points in the talks had long been Iran's stockpile of highly enriched uranium and the question of keeping the Strait of Hormuz open. Of late, however, the Lebanon front has emerged as the single biggest obstacle to any deal.

Iran has declared Israel's attacks on Lebanon a clear violation of a truce agreed upon with the United States, signaling both a possible suspension of negotiations and the threat of military retaliation.

Iran's Tasnim News Agency reported June 1 (local time) that Tehran's negotiating team had halted message exchanges with Washington aimed at reaching a war-ending agreement, in protest of Israel's strikes on Lebanon.

"The crimes of the Zionist regime in Lebanon continue," Tasnim said, adding that "Lebanon's stability was one of the core preconditions of the April 8 truce agreement, and the truce is now being violated on all fronts, including Lebanon."

The outlet said Iran's negotiating team had decided to suspend dialogue and document exchanges through intermediaries, and called for an immediate halt to Israeli military operations in Gaza and Lebanon and a full Israeli withdrawal from occupied Lebanese territory.

It added that "there will be no dialogue until the demands of Iran and the Axis of Resistance are met."

Iran's state broadcaster also said June 1 that "if Israel does not stop its attacks on Lebanon, the possibility of a truce between Iran and the United States will vanish."

Iran's Foreign Ministry issued a formal statement holding the United States directly responsible for Israel's truce violations and hinting at both a full breakdown of the ceasefire and possible retaliation. It stopped short of explicitly announcing a suspension of the nuclear negotiations.

"The United States bears direct responsibility for Israel's violations of the truce in Lebanon," the ministry said. "Violating the truce on even a single front means violating it on all fronts."

The ministry also signaled retaliatory intent, saying Iran "will continue to mobilize all its capabilities on the basis of the right to self-defense to protect its interests whenever necessary."

Senior Iranian officials involved in the US talks all emphasized June 1 that restoring the Lebanon truce was the top priority.

Foreign Minister Abbas Araghchi posted on X: "Immediate attention: It is clear that the Iran-US truce covers all fronts, including Lebanon. A violation on any one front constitutes a violation on all fronts. Whatever is violated, the United States and Israel bear responsibility for the consequences."

Mohammad Bagher Ghalibaf, speaker of parliament and head of Iran's negotiating team with the US, also posted on X, criticizing "the US maritime blockade and the escalating war crimes of the genocidal Zionist regime in Lebanon" as "clear evidence of US violations of the truce."

Foreign Ministry spokesperson Esmail Baghaei, speaking at a regular briefing, said the United States was behind "everything happening in Lebanon right now" and that "the Lebanon truce is the fundamental condition for all negotiations toward ending the war."

Iran's broad political, diplomatic and military influence across the Middle East rests on its network of proxy forces known as the Axis of Resistance. Among them, Lebanon's Hezbollah poses the most direct threat to Israeli security. Its stronghold in southern Lebanon borders Israel, allowing it to serve as a ground force that Iran itself cannot deploy in the area.

That is why Iran refuses to sideline Hezbollah even at the cost of the broader war-ending deal.

Khatam al-Anbiya Central Headquarters, which commands Iran's armed forces, warned that Prime Minister Benjamin Netanyahu had threatened to bomb Dahiyeh and Beirut and had ordered residents to evacuate. "Given the Zionist regime's repeated truce violations, if such threats are carried out, residents and military facilities in the northern part of the occupied territories — northern Israel — will need to evacuate," it said.

Tasnim also reported that Iran and the Axis of Resistance had decided to impose a full blockade on the Strait of Hormuz and activate new fronts — including the Bab el-Mandeb strait at the entrance to the Red Sea — to "punish" Israel and its backers.

The message was clear: if the Lebanon truce is not restored, new fronts will be opened.

Acting on Netanyahu's orders to intensify the offensive against Hezbollah, Israeli forces pushed beyond the "Yellow Line" — a control line drawn roughly 10 kilometers from the border — and on May 29 crossed the Litani River, about 30 kilometers north of the Blue Line that marks the border between the two countries.

Israeli forces have since seized Beaufort, a strategically important position north of the Litani River, rapidly expanding their operational zone.

Israel also resumed airstrikes on Beirut on May 28, the first such strikes in three weeks.

Netanyahu issued a fresh video warning June 1, saying "there will never be a situation where Hezbollah's terror headquarters in Dahiyeh remain a sanctuary while our cities and citizens are under attack." Dahiyeh is a predominantly Shia Muslim neighborhood on the southern outskirts of the Lebanese capital. Netanyahu ordered strikes there that day.

Following the prime minister's order, the Israeli military issued evacuation warnings to Dahiyeh residents, signaling another round of airstrikes.