Only five days after being inaugurated, President Donald Trump started taking action on his promise to remove millions of immigrants from the United States—or at least make their lives difficult.

Wednesday, Trump signed an order for the Secretary for Homeland Security to publish a list of crimes committed by immigrants each week. The order is intended to put political pressure on sanctuary cities, by positioning immigrants as criminals.

Publishing such a list, many worry, could also lead to private citizens attempting to take enforcement into their own hands.

Angela Fernandez, executive director of the Northern Manhattan Coalition for Immigrant Rights, called the measure "dangerous." 

"Their lives will be destroyed and they could become the victims of vigilante justice," she told DNAinfo. "They will not want to cooperate with the police on anything and some won't call the fire department or the hospital because they think it's all linked."

There are about 300 sanctuary cities across the U.S. Sanctuary cities can refuse to hand over undocumented immigrants to federal authorities through shielding policies.

The purpose of Trump's action, according to the order: “To better inform the public regarding the public safety threats associated with sanctuary jurisdictions, the Secretary shall utilize the Declined Detainer Outcome Report or its equivalent and, on a weekly basis, make public a comprehensive list of criminal actions committed by aliens and any jurisdiction that ignored or otherwise failed to honor any detainers with respect to such aliens.”

Take note that the order doesn’t specify pertinence to only to immigrants who entered the country illegally. Accordingly, crimes committed by legal immigrants could also be included.

As Trump signed the order, he read out the names of U.S. citizens who had been murdered by immigrants who entered the country without legal permission. As the Independent reports, there are an estimated 820,000 undocumented immigrants with criminal records in the United States.

The executive order claims it aims to “ensure the safety and territorial integrity of the United States,” adding that immigrants who may have entered the country illegally, or who were brought in as children, “present a significant threat to national security and public safety.”

During his presidential campaign Trump famously said, “We have some bad hombres, and we’re going to get them out.”

Trump initially promised to remove 11 million undocumented immigrants from the country within the first two years of his presidency, but he later walked back that promise to 2 or 3 million.