Friday’s U.S. government ban on non-essential travel at the border with Canada and Mexico was extended by the U.S. government to stop the spread of COVID-19, despite growing pressure to lift it.

The Biden administration was urged to lift the ban by U.S. border communities dependent on Canadian and Mexican shoppers. Canada has recently allowed fully vaccinated U.S. citizens to enter the country.

The Department of Homeland Security tweeted Friday to say that nonessential travel restrictions were necessary to limit the spread of COVID-19, and the delta variant. The ban was extended to Sept. 21 at the latest.

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DHS stated that it is working with medical and public health experts to determine the best way to safely and sustainably resume normal travel.

Travel restrictions were in place from March 2020, when the pandemic began. They have been repeatedly extended to allow commercial traffic and essential crossings to go on.