By Betsy Klein and Nadeen Ebrahim, CNN

(CNN) — US President Donald Trump said on Thursday that Washington is “very close” to reaching a nuclear deal with Iran after Tehran “sort of” agreed to its terms.

“Iran has sort of agreed to the terms: They’re not going to make, I call it, in a friendly way, nuclear dust. We’re not going to be making any nuclear dust in Iran,” he said.

Iranian officials haven’t publicly commented on Trump’s remarks, though the comments were reported by the country’s semi-official ISNA news agency. CNN has requested a comment from Iran’s mission to the United Nations.

Speaking at a business roundtable in the Qatari capital Doha, Trump reiterated that Iran “can’t have a nuclear weapon” and suggested that negotiators are “getting very close to maybe doing a deal.”

During his Gulf tour, Trump has repeatedly warned that Iran must never obtain a nuclear weapon, threatening to strike the country if it fails to reach a nuclear deal. But he has not explicitly ruled out Iran enriching uranium on its own soil. While uranium is used as a nuclear fuel, it can be weaponized if enriched to high levels.

Iran has said that its right to enrich uranium is non-negotiable, but the Trump administration has sent mixed signals on its position on the matter.

In an interview with Breitbart last week, US foreign envoy Steve Witkoff said that an enrichment program in Iran is a “red line” for the US. In an earlier interview with Fox News, he had suggested that Iran could be allowed to enrich uranium to low levels.

Several rounds of talks have taken place between the US and Iran, but the most recent one in the Omani capital Muscat last weekend was described by the Iranian foreign ministry spokesperson as “difficult.”

A senior Trump administration official gave a more positive assessment, telling CNN the discussions, which lasted over three hours, were encouraging.

Global oil prices fell after Trump’s comments. The price of a barrel of Brent crude, the global oil benchmark, fell over 3% Thursday morning to $64 a barrel. West Texas Intermediate, the US oil benchmark, was trading down 3.5% to almost $61 a barrel around the same time.

‘We are going to protect this country’

It is unclear what Trump meant by “nuclear dust,” but Gulf states, including Qatar, are concerned that an attack on Iran’s nuclear facilities could cause an environmental catastrophe in the region and drag them into a wider regional war.

Speaking in Doha, Trump vowed to “protect” Qatar.

“For this country in particular, because you’re right next door, you’re a stone’s throw away, not even, right? You’re a foot away. You can walk right into Iran. Other countries are much further away, so probably it’s not quite the same level of danger, but we are going to protect this country, this very special place with a special royal family,” he said.

Iranian President Masoud Pezeshkian lambasted the threatening remarks by Trump.

The US president “is naive for thinking that he can come to our region, threaten us, and hope that we back down against his demands,” Pezeshkian told a group of academics during a gathering in Kermanshah Province on Wednesday, according to the Iranian media. “We will never negotiate our dignity. This is in the blood of every Iranian,”

“You have tried to bring Iran to its knees for the past 47 years. We have existed for thousands of years and will continue as one for the years to come,” he said.

On Wednesday, Trump repeated his threats, saying he doesn’t want nuclear talks in Iran to take a “violent course.”

“Two courses, there’s only two courses. There aren’t three or four or five, there’s two. There’s a friendly and a non-friendly, and non-friendly is a violent course, and I don’t want that. I’ll say it up front. I don’t want that, but they have to get moving,” the president said.