US President Donald Trump faced mounting bipartisan pressure to set an example by wearing a face mask, as his health secretary warned the “window is closing” to gain control of an explosion of infections in conservative-led US states, AFP reported

“This is a very, very serious situation and the window is closing for us to take action and get this under control,” Health and Human Services Secretary Alex Azar said on CNN.

Azar was asked why Trump has refused to set an example by wearing a protective mask in public — even when standing next to mask wearing health advisors — and reiterated the White House explanation that the president is tested daily and is “in a unique position” as a world leader.

But many Republicans who are normally reluctant to criticise the president have been calling more insistently for mask use, with some urging a clearer example from the nation's leader.