US President Joe Biden has denied his administration bungled its response to the emergence of the Omicron variant.

He told a TV network that "nobody" could have predicted it. His top adviser Dr Anthony Fauci has said experts did foresee variants.

It comes a day after the White House unveiled plans to order 500 million at-home coronavirus tests amid a shortage.

There have been long waits for in-person tests as Christmas looms.

"I don't think it's a failure," Mr Biden said in a sit-down interview with ABC News on Wednesday. "I think it's - you could argue that we should have known a year ago, six months ago, two months ago, a month ago."

The Democratic president said he wished he "had thought" about ordering the 500 million test kits "two months ago".

One year ago Mr Biden lambasted a shortfall in Covid-19 testing under the Trump administration as "a travesty".

On Wednesday, New York City recorded nearly 29,000 new cases - a new single day record during the pandemic and a 30% jump from the record set earlier this week.

Pressed by ABC on US Vice-President Kamala Harris' remarks to the Los Angeles Times last week that the White House did not see Delta or Omicron coming, Mr Biden laughed.

"How did we get it wrong?" he responded. "Nobody saw it coming. Nobody in the whole world. Who saw it coming?"

On Tuesday, the White House also pledged to open more testing sites around the country.

In a briefing on Wednesday, Biden spokeswoman Jen Psaki was unable to provide specifics about how and when the free test kits would be distributed.

On Sunday, top White House coronavirus adviser Dr Fauci dismissed any suggestion that the emergence of new Covid variants could not have been predicted.

"We certainly were anticipating that there were going to be variants," he told CNN. "Because when you have so much replication going on in the community, if you give a virus enough opportunity to replicate you know it's going to ultimately mutate.

"And sometimes those mutations become a new variant, and that's what happened with Delta, and certainly with Omicron."

President Biden also told ABC News that he plans to run for re-election in 2024.

"But look, I'm a great respecter of fate. Fate has intervened in my life many, many times. If I'm in the health I'm in now, if I'm in good health, then in fact, I would run again," he said.

Mr Biden added that the chance of facing his predecessor, Donald Trump, "would increase the prospect of running".