On his second day in office, President Joe Biden has signed an executive order that will require international travelers, not only to have a negative COVID-19 test to enter the U.S., but also to self-quarantine upon arrival.

Previously, quarantine protocol for travelers had been issued only as unenforced guidance.

President Biden will also codify an action introduced by the Centers for Disease Control and Prevention (CDC) on January 12, which requires all visitors and returning residents to provide evidence of a negative COVID-19 test taken within 72 hours of departure for the U.S.

President Biden also signed an executive order today, requiring anyone using public forms of transportation, such as buses, trains and airplanes, to wear masks in transit, including while they’re in stations or airports.

This regulation pairs with yesterday’s executive order mandating that masks be worn by workers and visitors in all federal buildings and on government-controlled lands, including national parks and federal monuments.

The White House also today released a nearly-200-page document, titled the “National Strategy for the COVID-19 Response and Pandemic Preparedness” plan, which lays out a roadmap as to how the new administration intends upon tackling the COVID crisis as it currently stands.

In part, the document reads: “For international air travel, Executive Order ‘Promoting COVID-19 Safety in Domestic and International Travel’ requires a recent negative COVID-19 test result prior to departure and quarantine on arrival, consistent with CDC guidelines,” which was recently amended to 10 days.

The CDC also recommends getting tested again between three and five days after arrival and, if the second test is negative, allowing that the quarantine period may be shorted to seven days.

Details of the new quarantine mandate haven’t yet been hammered out just yet and President Biden has asked federal agencies to submit within the next 14 days their recommendations regarding the appropriate duration of quarantine, and acceptable timing and types of COVID tests under this order, within the next 14 days.