Biden says LA fires 'worst' in city's history

US President Joe Biden said Thursday the wildfires ravaging Los Angeles were the worst in California's history, as he pledged extra federal funds and resources to help the state.

"This is the most widespread, devastating fire in California's history," Biden said as he convened a special meeting of senior administration officials at the White House.

The outgoing president canceled a trip to Rome scheduled for Thursday to stay in Washington and coordinate the US government response to the fires, which have killed at least five people.

He said the federal government would cover 100 percent of costs of dealing with the disaster for the first 180 days, at the request of California's Democratic governor Gavin Newsom.

Biden said he was surging 400 federal firefighters and 30 firefighting planes and helicopters to Los Angeles, while the Pentagon will send eight large planes and 500 wildfire clearance personnel.