The US President Donald Trump has warned Iran that the "clock is ticking" as talks to bring the more than two-month old war to an end have stalled.
In a post on social media, Mr Trump threatened consequences for Iran if its leaders did not act quickly, saying there would be nothing left of the country if a peace deal was not agreed.
The post comes after the US President spoke with Israeli Prime Minister Benjamin Netanyahu to discuss Iran, an Israeli official reported.
Earlier, Iranian state media said the US had failed to make any concrete concessions in its latest response to Iran's proposed agenda for negotiations to end the war.
It comes as a drone strike caused a fire at a nuclear power plant in the United Arab Emirates, officials in Abu Dhabi said, at a time when progress appears to have stalled in efforts to end the US-Israeli war with Iran and restart shipping in the Gulf.
Emirati officials said they were investigating the source of the strike and that the UAE had the full right to respond to such "terrorist attacks". A diplomatic adviser to the UAE president said it represented a dangerous escalation, whether carried out by "the principal perpetrator" or one of its proxies.
The UAE has previously accused Iran of attacking its energy targets in what it has called an escalation of the conflict in the region.
The UAE defence ministry said two other drones had been "successfully" dealt with, and that the drones had been launched from the "western border". It did not elaborate.
The drone that got through hit an electrical generator outside the inner perimeter of the Barakah Nuclear Power Plant, the Abu Dhabi Media Office said. Radiological safety levels were unaffected and there were no injuries, it said.
The International Atomic Energy Agency said it was following the situation closely.
During the war that began with US and Israeli strikes against Iran on 28 February, Iran has repeatedly targeted the UAE and other Gulf states that host US military bases, hitting sites that include civilian and energy infrastructure.
Iran stepped up such attacks on the UAE earlier this month after Mr Trump announced a naval mission to try to open the Strait of Hormuz, which Mr Trump suspended after 48 hours.
More than five weeks after a tenuous ceasefire in the conflict took effect, US and Iranian demands remain far apart despite diplomatic efforts to end the war and reopen the strait, the world's most important shipping route for oil and gas.
The US has called for Iran to dismantle its nuclear programme and lift its hold on the strait. Iran has demanded compensation for war damage, an end to a US blockade of Iranian ports and a halt to fighting on all fronts, including in Lebanon, where Israel is battling Iran-backed Hezbollah.
Mr Trump, who held talks with Chinese President Xi Jinping this week without securing an indication from China that it would help resolve the conflict, has threatened to resume attacks if Iran does not agree to a deal.
A senior spokesperson for the Iranian armed forces, Abolfazl Shekarchi, said that if Mr Trump's threats were carried out, the US would "face new, aggressive, and surprise scenarios, and sink into a self-made quagmire".
Iranian foreign ministry spokesperson Esmaeil Baqaei said the US and Israel had tried to shift the blame for destabilising energy markets following their "unprovoked military aggression against Iran".
The disruption to shipping through the Strait of Hormuz has caused the biggest oil supply crisis in history, pushing up prices. The US has imposed its own blockade of Iranian ports.
Ebrahim Azizi, who heads the Iranian parliament's national security committee, said yesterday that Tehran had prepared a mechanism to manage traffic through the strait along a designated route that would be unveiled soon.
Thousands of Iranians were killed in the US and Israeli airstrikes. Thousands more have been killed in Lebanon in fighting between Israel and the Iran-backed group Hezbollah.
