US Vice President Mike Pence hailed Friday the nation's "truly remarkable progress" against coronavirus, although daily cases hit an all-time high of 40,000 a day earlier.

Speaking at the White House Coronavirus Task Force briefing, the first in almost two months, Pence said the reopening of America brought "encouraging news."

"There was a day two months ago when we lost 2,500 Americans in a single day. This week there were two days when we lost less than 300 Americans," Pence said.

He encouraged Americans to "take comfort in the fact that fatalities are declining."

Echoing President Donald Trump, he blamed the increased testing for the recent spike in case numbers.

"To one extent or another, the volume of new cases coming in is a reflection of a great success in expanding testing across the country," Pence said.

To date, more than 29.2 million tests have been conducted in the US, according to data from Johns Hopkins University.

Recent spikes in cases and hospitalizations forced some states including Texas, Florida and Arizona to pause their reopenings or reimpose new restrictions to curb the spread of the virus.

However, Director of the National Institute of Allergy and Infectious Diseases Anthony Fauci switched to a different tone than Pence and warned that some parts of the US are facing a "serious" problem over the spread of the pandemic.

The US is the worst-hit country by the pandemic with more than 2.4 million cases and over 124,700 fatalities. In all, more than 663,500 recoveries have been recorded.