First, Donald Trump scolded Chuck Schumer for criticising his administration and playing "politics." But then, the president panned the Senate Democratic leader during his nightly coronavirus briefing.

"Now is not the time for politics," Mr Trump said before the White House released a letter from the president back to Mr Schumer sharply rebuking him. The duo has feuded for years.

"Thank you for your Democrat public relations letter and incorrect sound bites, which are wrong in every way," Mr Trump wrote in a letter responding to one Mr Schumer wrote him urging him to put a military official in charge of distributing medical supplies to fight Covid-19.

"The existing federal leadership void has left America with an ugly spectacle in which States and cities are literally fending for themselves, often in conflict and competition with each other, when trying to procure precious medical supplies and equipment," the Senate minority leader wrote.

The two New Yorkers spoke by phone several times recently, but they decided to trade barbs on paper on Thursday as thousands more Americans tested positive for the disease.