WASHINGTON (AFP) - A top US health official said on Sunday (July 12) that with deaths from Covid-19 expected to continue rising in coming weeks, "everything should be on the table", including renewed lockdowns in hard-hit states.

"We're all very concerned," said Admiral Brett Giroir, the assistant secretary of health, on ABC's This Week. In particular, he called for the re-closing of bars, greater spacing in restaurants and the near-universal wearing of masks in the areas most afflicted, which are largely in southern states that reopened aggressively.

"For this to work we have to have 90 per cent of people wearing masks in public in the hot-spot areas," he said. "If we don't have that, we won't get control of the virus. It's absolutely essential."

His comments came one day after US President Donald Trump, who had long played down the importance of masks, appeared in public wearing one for the first time.

The federal Centres for Disease Control and Prevention had been calling for widespread mask-wearing since April.

Adm Giroir's comments came on a weekend when states across the country recorded new highs in coronavirus cases. Seven states set one-day death records this week.

The United States is the hardest-hit country in the world, with around 135,000 deaths and more than 3.2 million confirmed cases. Intensive care units in many hospitals are operating close to capacity.

But Adm Giroir stressed that progress is being made against the coronavirus pandemic, with more testing and new treatments available.

Asked about reported waits for testing of as long as 13 hours in hard-hit Arizona, Adm Giroir insisted that things were rapidly getting better.

"You'll see a lot more improvements in testing... over the next week or so," he said.

Amid growing and passionate debate over returning children to school in the fall - as Mr Trump and Education Secretary Betsy DeVos have insisted must be done - Adm Giroir said, "We do have to do that safely. We need to get the virus under control."

But with cases in many areas setting records by the day, he acknowledged that "we expect deaths to go up over the next two, three weeks before this turns around".

Adm Giroir said the administration is preparing for a challenging time in the fall, with the coronavirus likely resurging even as flu returns.

"There are some data that you can get both at the same time," he said. "That's not really good."