WASHINGTON, June 12, 2025 (AFP) - President Donald Trump said US personnel were being moved from the potentially "dangerous" Middle East on Wednesday as nuclear talks with Iran faltered and fears grew of a regional conflict.

Trump also reiterated that he would not allow Iran to have a nuclear weapon, amid mounting speculation that Israel could strike Tehran's facilities.

Iran threatened Wednesday to target US military bases in the region if conflict breaks out.

A US official had earlier said that staff levels at the embassy in Iraq were being reduced over security concerns, while there were reports that personnel were also being moved from Kuwait and Bahrain.

"Well they are being moved out because it could be a dangerous place," Trump told reporters in Washington when asked about the reports of personnel being moved.

"We've given notice to move out and we'll see what happens."

Trump then added: "They can't have a nuclear weapon, very simple. We're not going to allow that."

Tehran and Washington have held five rounds of talks since April to thrash out a new nuclear deal to replace the 2015 accord that Trump abandoned during his first term in 2018.

The two sides were due to meet again in coming days.

Trump had until recently expressed optimism about the talks, but said in an interview published Wednesday that he was "less confident" about reaching a nuclear deal.

Since returning to office in January, Trump has revived his "maximum pressure" campaign on Tehran, backing nuclear diplomacy but warning of military action if it fails.

The US president says he has pressed Israeli Prime Minister Benjamin Netanyahu to hold off striking Iran's nuclear facilities to give the talks a chance, but has increasingly signaled that he is losing patience.

Iran however warned it would respond to any attack.

"All its bases are within our reach, we have access to them, and without hesitation we will target all of them in the host countries," Iran's Defence Minister Aziz Nasirzadeh said in response to US threats of military action if the talks fail.

- 'Suffer more losses' -

"God willing, things won't reach that point, and the talks will succeed," the minister said, adding that the US side "will suffer more losses" if it came to conflict.

The United States has multiple bases in the Middle East, with the largest located in Qatar.

In January 2020, Iran fired missiles at bases in Iraq housing American troops in retaliation for the US strike that killed top Iranian general Qassem Soleimani days before at the Baghdad airport.

Dozens of US soldiers suffered traumatic brain injuries.

Amid the escalating tensions, the UK Maritime Trade Operations, run by the British navy, also advised ships to transit the Gulf with caution.

Iran and the United States have recently been locked in a diplomatic standoff over Iran's uranium enrichment, with Tehran defending it as a "non-negotiable" right and Washington calling it a "red line."

Iran currently enriches uranium to 60 percent, far above the 3.67-percent limit set in the 2015 deal and close though still short of the 90 percent needed for a nuclear warhead.

Western countries have long accused Iran of seeking to acquire atomic weapons, while Tehran insists its nuclear program is for peaceful purposes.

Last week, Iran's supreme leader Ayatollah Ali Khamenei said enrichment is "key" to Iran's nuclear program and that Washington "cannot have a say" on the issue.

During an interview with the New York Post's podcast "Pod Force One," which was recorded on Monday, Trump said he was losing hope a deal could be reached.

"I don't know. I did think so, and I'm getting more and more -- less confident about it. They seem to be delaying and I think that's a shame. I am less confident now than I would have been a couple of months ago," he said.

Iran has said it will present a counter-proposal to the latest draft from Washington, which it had criticised for failing to offer relief from sanctions -- a key demand for Tehran, which has been reeling under their weight for years.