US President Donald Trump said Los Angeles and San Diego could face destruction during a war with Iran, while arguing that even such losses could be an acceptable price for achieving victory.

Speaking to voters in Nebraska, Trump said he expects a major victory over Iran that would demonstrate that his administration had chosen the right course.

The US president also described higher prices caused by the military conflict as a temporary and acceptable cost of ensuring the security of the United States and the wider world. He believes the confrontation with Tehran is approaching its end, although Iran could attempt to prolong it.

Trump previously suggested that the conflict could conclude around the November 3 midterm elections, either shortly before or after the vote. At the same time, he said he remains open to direct negotiations with Iran.

Talks between Washington and Tehran have reached a deadlock, with Qatari mediation efforts failing to produce diplomatic progress.

Following the breakdown of negotiations, US Secretary of State Marco Rubio demanded that the Iranian delegation attending the UN General Assembly immediately leave the country. Iranian representatives departed for Doha several hours later.

Trump has also threatened to bomb Iran if a deal ultimately fails, describing Tehran as an irrational partner. He maintained that the situation should be resolved in the near future.