US President Donald Trump clashed with Los Angeles Mayor Karen Bass during a fire emergency briefing in the Pacific Palisades, California.
Residents expressed their frustration over being prevented from returning to their homes sooner.
Ms Bass said debris was causing the delay and residents' safety was the city's priority. Mr Trump urged Ms Bass to speed up the process.
"You have emergency powers just like I do. And I'm exercising my emergency powers. You have to exercise them also," he said.
Mr Trump has sharply criticised California's response to the wildfires, which have caused widespread destruction this month. He said he would work with California Governor Gavin Newsom to respond to the Los Angeles fires after earlier floating doing away with the Federal Emergency Management Agency.
Mr Newsom, a Democrat who has had a tense relationship with the Republican leader, told Mr Trump that California would need his support.
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Mr Trump has vowed to sign an executive order to overhaul or eliminate FEMA, the main federal agency that responds to natural disasters.
"FEMA is a very expensive, in my opinion, mostly failed situation. We had great people. We did some great jobs. But each state should take care of their problem and get money from the federal government. It would be so much better, so much more efficient," he said.
Mr Trump has accused Mr Newsom and Ms Bass of "gross incompetence" and threatened to withhold aid to California.
