WASHINGTON, United States (AP) — Federal officials are extending the requirement for masks on planes and public transportation for one more month — through mid-April — while taking steps that could lead to lifting the rule.

The mask mandate was scheduled to expire March 18, but the Transportation Security Administration said Thursday that it will extend the requirement through April 18.

TSA said the extra month will give the US Centers for Disease Control and Prevention time to develop new, more targeted policies that will consider the number of cases of COVID-19 nationally and in local communities, and the risk of new variants.

The TSA enforces the mask rule, which extends to planes, buses, trains and transit hubs.

As of March 3, more than 90 percent of the US population lived in areas with low or medium COVID-19 case levels, meaning that the CDC no longer recommends face masks in public indoor settings.

A decision to eventually scrap the mask requirement — one of the last vestiges of nationwide pandemic rules — has grown more likely in recent weeks as more states, even those led by Democratic governors, relaxed their own mandates for wearing masks indoors, and the CDC eased its recommendations.

White House press secretary Jen Psaki said Thursday that deciding on the right policy for travel was more complicated than setting standards for local communities to follow.

“If you’re moving from one zone to another and picking people up … it’s a little bit different, and that requires some consultation, which is what (CDC officials) are going to endeavor to do between now and April 18,” Psaki said.

CDC Director Dr Rochelle Walensky said last week that her agency must study the science around virus transmission “but also the epidemiology and the frequency that we may encounter a variant of concern or a variant of interest in our travel corridors.”

The federal mask mandate was imposed in January 2021, days after President Joe Biden took office, and has been extended several times. The Trump administration had declined to require masks on public transportation, but airlines began requiring them in mid-2020 to reassure passengers worried about contracting the virus.