Trump told reporters at the White House that he had been just "an hour away" from relaunching Washington's attacks on Iran before postponing the order, after weeks of a fragile ceasefire and talks to end the war, which began on February 28.

"You know how it is to negotiate with a country where you're beating them badly. They come to the table, they're begging to make a deal," he said.

"I hope we don't have to do the war, but we may have to give them another big hit. I'm not sure yet."

Iran, as well as many observers, dispute Trump's take on the power dynamics and note that Tehran has been able to exert leverage through control over the vital Strait of Hormuz, driving up global oil prices.

Iran's army spokesman Mohammad Akraminia earlier warned the Islamic republic would "open new fronts against" the United States if it restarted its attacks.

He added that Iran's military had used the ceasefire as an opportunity "to strengthen its combat capabilities."

Trump offered a deadline of several days for resuming strikes if a deal was not agreed.

"I'm saying two or three days, maybe Friday, Saturday, Sunday, something, maybe early next week, a limited period of time," he said.

Trump's new deadline came after he said on Monday that Gulf leaders had asked him to hold off on an attack at the 11th hour.

Vice President JD Vance, who negotiated with Iran in failed talks in Pakistan, also said that the United States was "locked and loaded" but voiced hope for a diplomatic solution.

"A lot of good progress is being made, but we're just going to keep on working at it, and eventually we'll either hit a deal or we won't," Vance, described as a skeptic of the unpopular war, told reporters at the White House.

Trump had already indefinitely extended the truce and made clear he wants to exit a war that has proven to be a political liability, with Iran's control of the Strait of Hormuz rattling the global economy and hurting Americans at the pump.

Iran's Deputy Foreign Minister Kazem Gharibabadi wrote on X that Trump's comments meant the US leader was "calling a 'threat' a 'chance for peace'!"

- Drone attack -

Since the ceasefire took hold on April 8, Tehran and Washington have held only the single round of talks involving Vance.

Iran's cleric-run state has proven resilient, though its supreme leader was killed on the first day of the war, and is demanding the release of Iranian assets frozen abroad and the lifting of long-standing sanctions.

After the Iranian threat of attacks on new fronts, the United Arab Emirates said a drone attack on its Barakah nuclear power plant last week originated from Iraqi territory, where Iran backs groups accused of launching attacks on Gulf nations in the war.

A top Emirati official had already suggested Iran or one of its regional proxies was to blame.

Iran has been ramping up military pressure in the region.

The Revolutionary Guards, the ideological arm of Iran's military, threatened on Monday to put the internet fiber optic cables passing through the Strait of Hormuz under a system of permits.

Its Revolutionary Guards also said Monday that they struck groups linked to the United States and Israel within the Iranian province of Kurdistan, near the border with Iraq.

- 'Excessive' conditions -

Iran's foreign ministry said it has responded to the latest US proposal, which Iranian media described as "excessive" and offering "no tangible concessions."

The Tasnim news agency, citing an unnamed source close to the Iranian negotiating team, said the United States made one new step forward in the latest text by agreeing to waive oil sanctions while negotiations were underway.

Iran has also demanded an end to Israel's strikes in Lebanon, which began in retaliation for fire by Iranian-backed Shia movement Hezbollah.

The Israeli military on Tuesday launched a series of strikes across Lebanon and warned residents of a dozen towns to flee ahead of the attacks.

Israel and Lebanon's central government have in place a twice-extended ceasefire, but Israel says it does not apply to its attacks on Hezbollah.

In one possible sign of diplomatic progress, a rights group said that an Iranian citizen who holds US permanent residency was released from prison and returned to the United States.

Shahab Dalili had served 10 years in prison after a sentence for allegedly "cooperating with a hostile government," the Human Rights Activists News Agency said.