President Donald Trump announced new federal guidelines on Friday recommending that Americans wear face coverings in public to help fight the spread of coronavirus.

But he immediately said he had no intention of following the advice himself, saying: “I’m choosing not to do it.”

The new guidance from the Centres for Disease Control and Prevention encourages people, especially in areas hit hard by the spread of coronavirus, to use rudimentary coverings like T-shirts and non-medical masks to cover their faces while outdoors.

The president exempted himself from his administration’s own guidelines, saying he could not envision himself covering his face while sitting in the Oval Office greeting world leaders.

“It’s a recommendation, they recommend it,” Mr Trump said. “I just don’t want to wear one myself.”

The new guidance, announced at a time when states in the US are bracing for critical shortfalls like those that other parts of the world have experienced, raises concern that it could cause a sudden run on masks if Americans turn to private industry to meet the expected surge in demand.

Mr Trump and other administration officials sought to minimise any burden by stressing the recommendations did not amount to requirements and a variety of homemade coverings were perfectly acceptable.

Federal officials stressed that surgical masks and N95 respirators should be left for those on the front lines of fighting the spread of the infection.

Friday’s announcement capped an evolution in messaging from the White House that officials acknowledged has at times been confusing.

First lady Melania Trump embodied the ever-changing messaging with a tweet saying: “As the weekend approaches I ask that everyone take social distancing & wearing a mask/face covering seriously.”

The administration has said states should have done more to stockpile medical supplies, but it is not clear if anyone is prepared for the potential rush that could ensue if people try to obtain medical masks for themselves.

As with other public health guidance, the recommendation on face covering has been a moving target for the administration. Under the previous guidance, only the sick or those at high risk of complications from the respiratory illness were advised to wear masks.