The US state department is to advise Americans to avoid 80% of countries worldwide because of the coronavirus pandemic.
In a note to the media about its updated travel guidance, it said the pandemic continued to "pose unprecedented risks to travellers".
The current US "Do Not Travel" advisory covers 34 out of 200 countries.
Covid-19 has now claimed more than three million lives worldwide - more than half a million of them in the US.
The World Health Organization (WHO) warned the world was "approaching the highest rate of infection" so far, despite the global rollout of vaccination programmes.
