WASHINGTON — President Biden on 2 December announced plans to tighten up Covid-19 testing timelines for travellers entering the US and extend a mask mandate on airplanes and other public transportation as part of a broad administration effort to combat the Omicron variant.

International travellers coming to the US will have to test within a day of departure, regardless of vaccination status, rather than the 72 hours currently required for vaccinated travellers, Biden said. The new testing rules will take effect on 6 December, at 12:01 a.m. ET, according to a senior administration official who said airline industry representatives were notified of the timing on 2 December. The requirements apply both to US citizens and foreign nationals flying into the country.