US Vice-President Mike Pence has visited a top US hospital without wearing a mask, despite the medical centre’s own rules that visitors wear personal protective equipment.
Mr Pence appeared to be the only person present not in a facial covering at the Mayo Clinic in Minnesota.
In a deleted tweet, the clinic said the vice-president had been notified in advance of its policy requiring masks.
Mr Pence leads the White House coronavirus taskforce.
The US government’s own coronavirus-prevention advice is that people should wear face coverings “in public settings where other social distancing measures are difficult to maintain”.
The Mayo Clinic itself requires all patients and visitors to its medical centres to wear a mask or face covering.
Mr Pence’s visit came on the same day that the US coronavirus caseload topped one million and the number of deaths surpassed 57,000.
President Donald Trump has himself previously said he has no plans to wear a mask.