In the latest effort to tighten travel restrictions to limit the spread of the novel coronavirus, President Trump has ordered the closure of the border between the U.S. and Mexico to all but essential travel. This move follows an announcement earlier this week that both America and Canada agreed mutually to close their shared border to non-essential travel for at least 30 days, while it remains open for urgent, necessary business and commercial traffic.

Trump had also already taken steps to minimize border crossings at the Mexican border, taking additional steps to block migrants and asylum seekers on top of what measures are are already in place, as reported by CNN earlier this week. The U.S. also issued a “do not travel” warning to its own citizens on Thursday, which broadly advises against traveling to any international destination. Trump has also said that internal travel restrictions are not out of the question pending the pandemic’s progress.

U.S. Secretary of State Mike Pompeo announced the closure of the U.S.-Mexican border on Friday, noting that it was decided in collaboration with the Mexican government. Earlier on Friday, Trump said that the U.S. and Mexico are suspending “non-essential travel,” not related to trade and commerce, education, and medical purposes, at all ports of entry, which mirrors the moves made with Canada. He added that Mexico is also suspending air travel from Europe, which will help “protect the southern border” of the U.S., as well.

Trump added that both the Canadian and Mexican borders are being treated equally in this instance, in terms of the actions taken to limit cross-border travel. The border closure between the U.S. and Mexico will take effect beginning on Saturday, March 21st.

On Saturday at midnight, the U.S. will also implement “CDC recommendations” to immediately institute blanket refusal of entry for anyone on both the northern and southern U.S. border that does not have proper documentation for lawful entry. This replaces the existing practice of processing and holding in Customs and Border Protection (CBP) facilities at the border those attempting to cross. Trump later clarified that all attempted border crossing individual will be returned to their original country of citizenship.

It’s an extreme step, and the White House claims that it’s been made to address the fact that border facilities are unable to follow CDC best practices for avoiding COVID-19 transmission while continuing to deal with migrants in the existing manor. This does mean blanket rejection even of individuals seeking political asylum and refugee status, however, which has dangerous connotations in terms of compassionate and human rights-related entry. Still, NIH representative and White House coronavirus task force member Dr. Anthony Fauci noted in Friday’s briefing that in order to ensure that border closure measures are effective, they must apply equally to all means of entry to the country.