A Republican candidate in San Diego has criticized Donald Trump after the US president suggested Iran could “take out” the city or Los Angeles.

Trump has faced a chorus of condemnation from Democratic leaders in California after his comments at a rally in Nebraska on Monday night. Republicans have largely remained silent.

But Republican Jim Desmond, who is standing in a competitive San Diego based seat in the House of Representatives, pushed back.

“America must stand up to Iran and defend our interests, but the first responsibility of our Commander in Chief is to protect the American people and our homeland,” Desmond, the former mayor of San Marcos, said in a statement.

He joined a string of prominent Democrats who called out the comments. Hakeem Jeffries, the House minority leader, said: “The nuclear annihilation of an American city is no laughing matter.”

Desmond is set to face Marni Von Wilpert, a lawyer and member of San Diego’s city council, for the state’s 48th congressional district – which was redrawn in response to Proposition 50.

Desmond, also a navy veteran, said that he “served to protect Americans, not write off American cities as an acceptable price of war”.

It’s a notable rebuke from a Republican in a closely watched contest that could help the party retain their razor-thin majority in the lower chamber.

“No American city is expendable, and no American family should ever be treated as collateral damage,” Desmond added.

At his rally in Nebraska, Trump claimed that high prices due to the war with Iran are a “small price to pay for keeping the world safe – keeping our country safe”. He went on: “They can take out a city. Let them take out Los Angeles. Let them take out San Diego.” The crowd clapped.

Within hours there was criticism from California governor Gavin Newsom and others. On Tuesday the backlash continued.

Terra Lawson-Remer, chair of the San Diego board of supervisors, said in a statement: “My grandfather was a Marine. He died fighting for our country … When the Commander in Chief talks about San Diego being ‘taken out’ by other countries with whom we’re at war, he is not fit to lead. Trump is a traitor to our security, to our values, and to our Country.”

Tom Cochran, head of the United States Conference of Mayors, argued that Trump had “crossed a line that no president should ever approach”. He added: “No American President should ever describe an attack on an American city by a hostile foreign power as acceptable. Not at a rally, not as a joke, not under any circumstances.”

But Trump supporters dismissed the uproar. Blake Marnell, who wears a brick-patterned suit to resemble Trump’s border wall, lives in San Diego and was at the rally in Nebraska. He said by phone on Tuesday: “I defend his comments absolutely. It is not inappropriate to mention something like that now because you have to take it in the context in which it is spoken. If you look at that context, it’s appropriate for a rally in which the president is is addressing his base.”

Marnell added: “The Democrats have a long and storied history of flying off the handle at any remark that President Trump makes, and this is just another chapter in that history, and I ascribe no significance to it, and in two days no one will be talking about it.”

The White House also insisted that Trump was being willfully misinterpreted.

Steven Cheung, its director of communications, posted on X: “The media freakout over President Trump’s comments is not rooted in reality. He was clearly stating U.S. cities would have been threatened if a nuclear Iran hadn’t been stopped. America is safer because of the President. Iran has no nuclear, no navy, no air force, and no money.”

The White House’s “Rapid Response 47” account called the Los Angeles Times newspaper “buffoons” and insisted that Trump was saying the US is “fighting to STOP Iran from having the ability to take out LA and San Diego with a nuclear weapon – which they would if they had the chance.”