President Trump has said he is not happy with Iran in the wake of the latest talks on its nuclear programme, but said he had not yet decided whether to attack the country.

"I'm not happy with the fact that they're not willing to give us what we have to have. So I'm not thrilled," Trump said in his first comments on negotiations in Geneva that broke up on Thursday without a deal.

The US president stressed that he did not want to use military force against Iran, but said sometimes "you have to".

Concern over the prospect of US strikes against Iran led a number of countries to issue warnings to their citizens in the region on Friday.

The UK temporarily withdrew staff from its embassy in Tehran and updated its travel guidance to advise against "all but essential travel" to Israel.

Countries including China, India and Canada urgedtheir citizens to leave Iran as soon as possible due to the prospectof hostilities. Germany advised "urgently" against travel to Israel while France reiterated its advice not to do so.

Meanwhile, the US urged its citizens in Iran to leave "immediately". Itsembassy in Israel also told some non-emergency staff and their families they could leave the country,advising that they may wish to do so "while commercial flights are available".

Trump has threatened military action against Tehran if it does not reach a deal about its nuclear ambitions.

He has ordered the largest US military build-up in the Middle East since the US-led invasion of Iraq in 2003, while Iran has vowed to respond to an attack with force.

Washington and its allies suspect Iran is moving towards developing a nuclear weapon, which Tehran has always denied. It claims its programme is intended for peaceful, civilian purposes despite having enriched uranium up to near weapons-grade level.

The president told reporters on Friday: "I say no enrichment... I think it's uncivil."

It came as Oman's Foreign Minister Badr Albusaidi, who was mediating the talks, said Tehran had agreed never to stockpile enriched uranium, making "the enrichment argument less relevant".

"If you cannot stockpile material that is enriched then there is no way you can actually create a bomb," Albusaidi told CBS News.

He had said on Thursday that US and Iranian officials made "significant progress" in the high-stakes nuclear talks in Geneva, but the chances of a deal that could avert a war remain unclear.

Albusaidi said the two sides planned to resume negotiations "soon" after consultations in their capitals, and technical-level discussions would take place next week in Vienna.

Iran's Foreign Minister Abbas Araghchi, who led his country's delegation, said "good progress" had been made but while there had been agreement on some issues, differences remained on others.

He said more negotiations would happen in a less than a week. President Trump's comments on Friday were the first official reaction from the US.

Meanwhile, the State Department announced US Secretary of State Marco Rubio would travel to Israel on Monday, where he is expected to meet Prime Minister Benjamin Netanyahu and discuss "a range of regional priorities", including Iran.

Rubio also said on Friday he had designated Iran a "state sponsor of wrongful detention". It marked the first use of a power created in September under which the US can sanction or take other measures against countries unjustly detaining its citizens.

"We reiterate our call for Americans who are currently in Iran to leave immediately," he said in his statement announcing the move.

Earlier, US Ambassador to Israel Mike Huckabee advised embassy staff who wished to leave Israel to "do so TODAY", the New York Times reported.

Hereportedly said in email there was "no need to panic, but for those desiring to leave, it's important to make plans to depart sooner rather than later".

A statement on the embassy's website said they "may wish to consider leaving Israel while commercial flights are available".

It came days after the US government ordered all non-essential staff to leave its embassy in the Lebanese capital of Beirut, following a security review.

Vice-President JD Vance had told the Washington Post on Thursday that strikes remained under consideration - but there was "no chance" of the US becoming involved in a drawn-out war.

"I think we all prefer the diplomatic option," Vance said. "But it really depends on what the Iranians do and what they say."

The US has sent thousands of troops and what Trump has described as an "armada" to the region in recent weeks, including two aircraft carriers along with other warships, as well as fighter jets and refuelling aircraft.

He said on 19 February that the world would find out within 10 days whether the US would reach a deal with Iran, or take military action.

"We have to make a meaningful deal otherwise bad things happen," Trump said at the time.

Iran claims its enrichment activity stopped after the US bombed three of its nuclear sites in June, joining Tehran's conflict with Israel. Trump said at the time they had "obliterated" the facilities.

The UN's nuclear watchdog said on Friday that it had been refused access to the uranium enrichment sites ever since, calling it a cause of growing concern.

In a confidential report to its member states, the International Atomic Energy Agency said it was critical that its staff inspect the nuclear sites without delay.