US President Donald Trump said Tuesday that the Strait of Hormuz will reopen “very soon” as negotiations with Iran continue while warning Tehran that the United States would take strong military action if a deal is not reached.

“The Strait is going to be open very soon — or they’re gonna hit very hard, and then the Strait is going to be open,” he told Fox News.

Trump said he had previously been prepared to launch a major attack against Iran but agreed to negotiations after Iranian officials requested talks.

“We were going to a tremendous attack, the biggest since World War II, and they called me and said, very politely, ‘Please, can we talk? Can we talk?’… I said, ‘Yes, we can talk. Let’s get it done. Finally, let’s get it done,'” he added.

The president said Iran would face a severe response if it abandoned negotiations, reiterating that Tehran cannot be allowed to develop a nuclear weapon.

“If they back out again, they’re going to get hit really hard. They know that; they understand that. I have no choice. They can’t have a nuclear weapon. It’s very simple,” he said.

Trump said US and Iranian officials were engaged in “very good discussions,” though he acknowledged that Tehran has not publicly confirmed the progress.

“The only thing that matters is action, and they want to make a deal. We’ll see what happens,” he said. “If they don’t make a deal, it’s going to be too bad.”

Oil prices fell, and stocks jumped in Asian trade on Wednesday after Wall Street hit record highs on hopes that a deal could soon be reached to restore traffic through the blockaded Strait of Hormuz.

‘They had an all-day negotiation today’

Trump said there was an “all-day negotiation” on Tuesday with Iran.

“They had an all-day negotiation today, and it looks like things are very good. And if that happens, where the Strait has opened up … but if the Strait opens up, and it’s partially opened anyway, and as you know, we control the Strait totally through the blockade. But if we have no friction, then oil will go down to, I think it’ll go down to $2.50 a gallon,” he added, referring to retail gas prices.

Trump said that the oil companies have got to start lowering gas prices.

Later, speaking to reporters in the state of California, he said the US is “moving along very nicely” with Iran.

“We’re moving along very nicely. We’ll find out. We’ll know in 48 hours,” he added.

The US, Iran and Oman are nearing an interim agreement aimed at reopening the Strait of Hormuz and restoring a ceasefire between Washington and Tehran, with a possible announcement expected as early as Wednesday, the Axios news site reported Tuesday.

Earlier Tuesday, US Secretary of State Marco Rubio said Washington and Tehran have yet to finalise talks on passage through crucial international waterways, but he hopes an agreement will come “very shortly.”

Read: Pakistan, Qatar preparing document for reopening Hormuz amid indirect US-Iran contacts: sources

However, Iranian state media, citing an informed source, said an agreement with Oman on the strait, which normally carries about a fifth of global oil and liquefied natural gas shipments, will be delayed “as long as the United States continues to threaten Iran.”

Qatar also cites progress in talks

Trump has yet to achieve the objectives he set out at the start of the war: dismantling Iran’s nuclear programme, curbing its ability to attack regional rivals and creating conditions for Iranians to overthrow their clerical rulers.

Iran has halted most traffic through Hormuz while Washington maintains a blockade of Iran-related shipping and ports.

Qatar had earlier said mediators were making progress in efforts to end the conflict, even after Tehran denied that talks were underway.

Trump and Qatar’s Emir Sheikh Tamim bin Hamad Al Thani discussed efforts to narrow differences between Washington and Tehran and improve the prospects for a lasting settlement during a phone call on Tuesday, Qatar’s Emiri office said.

Iran’s Foreign Ministry spokesperson, Esmaeil Baghaei, said talks with Oman over transit through the strait were positive and continuing, and were focused on establishing safe shipping lanes, state media reported. He added the route being negotiated was aimed at ensuring the sovereign rights and national security of both Iran and Oman.

Read more: How Iran is widening its pressure campaign to force US concessions

Iran has long demanded control over the Strait of Hormuz, which it says it should share with Oman on the opposite shore. But Tehran rejected an Omani proposal last week that would have allowed shared oversight and the collection of voluntary fees from ships.

Yemen’s Iran-aligned Houthis have also imposed a naval blockade on Saudi Arabia in the Red Sea, further restricting oil export routes. A projectile struck an Indian-flagged vessel near Yemen, causing it to capsize and sink, but all 14 seafarers on board were rescued, Indian officials said, in an attack Yemen blamed on the Houthis.

The United Nations’ International Maritime Organisation has reported at least 17 deaths of seafarers from 64 incidents in the Strait of Hormuz since the war started on February 28.

Those are in addition to the Iranian government’s toll of 50 people killed and 500 wounded by US strikes since hostilities renewed in late June, a figure reported before Iran said a US strike on Qeshm in late July killed a husband and wife and their 2-year-old son.

In all, 3,400 civilian deaths in Iran and thousands more in Lebanon have been recorded since the US and Israel launched the war on February 28, while the US has reported 18 military personnel dead.

Israeli officials question Trump’s push for Iran deal, say Washington seeks agreement ‘at any cost’

Israeli officials have expressed scepticism over the latest US diplomatic efforts with Iran, arguing that President Donald Trump and his advisers are pursuing an agreement “at any cost,” according to Israeli broadcaster Channel 12.

Citing a senior Israeli official, the report said there is growing uncertainty in Tel Aviv over Trump’s approach toward Tehran.

“The distance between peace and war with Trump is the distance between the letters T, R and U on the keyboard,” the official told Channel 12, suggesting that US policy could shift rapidly.

According to the broadcaster, Washington has not been directly briefing Israel on negotiations with Iran concerning the Strait of Hormuz, leaving Israeli authorities to obtain most updates through indirect channels.

Channel 12 reported that Israeli officials privately mocked the renewed diplomatic push, saying any potential agreement could regulate operations in the strategic waterway and pave the way for Washington and Tehran to restore a previous understanding.