US President Donald Trump threatened to cut off funding to schools that do not open in the fall and criticised the federal health agency's guidelines for reopening schools as “very tough & expensive", according to AFP.

“The Dems think it would be bad for them politically if US schools open before the November election, but [it is] important for the children & families. May cut off funding if not open," Trump said on Twitter, pointing to schools reopening in some European countries with no problems.

Trump also took aim at the US Centres for Disease Control and Prevention, the nation's health protection agency whose director sits on the White House coronavirus task force.