Biden warns about Trump's impact on US states

US President Joe Biden has warned that former president Donald Trump's hold on the Republican Party would spill into state government, during an event to boost Democrat Tina Kotek in Oregon's tight race for governor.

Biden, who is finishing a western travel swing that included stops in Colorado and California, visited Oregon on Saturday in part to help Kotek, who supporters hope will keep the governorship in Democratic hands in a state the president won handily in 2020.

Kotek is running against Republican Christine Drazan and an independent candidate, Betsy Johnson, a former Democrat who is financially backed by Nike co-founder Phil Knight. Recent public opinion polls suggest Drazan has pulled into the lead.

Biden, a Democrat, praised Kotek as an "articulate, tough, committed woman" and emphasised the stakes of state leadership contests.

"As long as Trump controls the Republican Party, he's going to have incredible impact on state legislative bodies," and state government, Biden said at a reception for Kotek.

He said the role of governors in the country was increasing exponentially and said Kotek's race mattered well beyond Oregon.

"She's rational. She's smart," he said of Kotek.

Thirty-six of the 50 US states will elect governors in November's US elections, with potential impact on abortion access, education and future state elections.

Trump has falsely asserted that the 2020 presidential election he lost was marred by widespread fraud.

Biden on Truss and Iran

Biden said he was not the only one who thought British Prime Minister Liz Truss' original economic plan, which has led to a steep dive in the value of the pound, was a mistake.

"I wasn't the only one that thought it was a mistake." He told reporters during a stop at an ice cream shop in Oregon.

The White House has refrained from commenting on Truss' problems.

Later, Biden said he was surprised by the courage of the people taking to the streets in protest in Iran.

Biden, speaking in Portland after campaigning for a fellow Democrat in Oregon, was commenting on the weeks of unrest in Iran since a young woman died in police custody.