WASHINGTON (AFP) - US President Donald Trump rounded on House Speaker Nancy Pelosi on Wednesday (Sept 2) after she was caught on camera visiting a San Francisco hair salon in breach of coronavirus lockdown rules - and with her face mask removed.

The Democrat, a bete noire for Trump and his supporters, regularly hounds the billionaire Republican for his handling of the pandemic, which has killed more than 180,000 people in the United States.

In June, she targeted his procrastination over endorsing the use of face masks, widely seen as one of the most effective ways of controlling infection rates.

"Real men wear masks," she said.

Trump was not seen wearing one publicly until July.

Surveillance footage shows Pelosi walking from room to room inside the hair salon on Monday with her face mask removed.

Such treatments are still banned indoors in San Francisco as part of restrictions aimed at containing the spread of the virus.

"Crazy Nancy Pelosi is being decimated for having a beauty parlor opened, when all others are closed, and for not wearing a Mask - despite constantly lecturing everyone else," the president tweeted, using one of his favourite mocking nicknames.

Pelosi's deputy chief of staff, Drew Hamill, said she "always wears a mask and complies with local Covid requirements."

"This business offered for the Speaker to come in on Monday and told her they were allowed by the city to have one customer at a time in the business. The Speaker complied with the rules as presented to her by this establishment," he said.