US President Donald Trump says he was surprised by a warning this week from top US infectious disease expert Anthony Fauci about the dangers of reopening the economy too quickly.

“To me it’s not an acceptable answer,” Trump told reporters at the White House about the warning Fauci presented in testimony to the US Senate on Tuesday.

Trump on Wednesday also said he still strongly believed the Federal Reserve should have negative interest rates, but he gave a modicum of approval to Fed Chair Jerome Powell who said earlier in the day the central bank would not lower rates beyond zero.

Trump said Powell, whom he frequently criticises, has improved in his performance as the Fed’s head, but he still disagrees with Powell when it comes to the lending rate set by the central bank.

Powell earlier on Wednesday said the Fed is still not looking at setting rates below zero, and instead pushed lawmakers to use spending to boost the economy during the deadly coronavirus pandemic.

Trump also said a $US3 trillion-plus coronavirus relief package proposed by Democrats in the US House of Representatives was dead on arrival.

The Democratic proposal, which includes funding for states, businesses, food support and families, was quickly rejected by Trump’s fellow Republicans in the US Senate after it was unveiled on Tuesday.