_{Editor's note: This story has been updated with a statement from U.S. Rep. Michael McCaul.}

The Trump administration on Tuesday moved one step closer to implementing the president’s plans to aggressively rid the country of undocumented immigrants and expand local police-based enforcement of border security operations.

In a fact sheet outlining the efforts, the Department of Homeland Security said that though their top priority is finding and removing undocumented immigrants with criminal histories, millions more may also be subject to immediate removal. 

“With extremely limited exceptions, DHS will not exempt classes or categories of removal aliens from potential enforcement. All of those in violation of the immigration laws may be subject to enforcement proceedings, up to and including removal from the United States,” the fact sheet explains. “The guidance makes clear, however, that ICE should prioritize several categories of removable aliens who have committed crimes, beginning with those convicted of a criminal offense.”

The memo did not include instructions to halt the 2012 executive action called Deferred Action for Childhood Arrivals, or DACA, which has allowed about 750,000 undocumented immigrants who arrived in the United States as children to live and work in the country legally.

The guidelines also state that the Department of Homeland Security has authority to expedite the removal of undocumented immigrants who have been in the country illegally for at least two years, a departure from the Obama administration's approach of concentrating mainly on newly arriving immigrants.

“To date, expedited removal has been exercised only for aliens encountered within 100 air miles of the border and 14 days of entry, and aliens who arrived in the United States by sea other than at a port of entry,” the agency states.

The action also seeks to expand a police-based immigration enforcement program known as 287(g), which allows local and state officers to perform immigration duties if they undergo the requisite training. The program fell out of favor under the Obama administration after Immigration and Customs Enforcement announced in 2012 that it wouldn’t renew contracts that were in place at the time.

“Empowering state and local law enforcement agencies to assist in the enforcement of federal immigration law is critical to an effective enforcement strategy, and CBP and ICE will work with interested and eligible jurisdictions," the memo reads. 

Expansion of the 287(g) program will be concentrated on the “border regions,” according to the memo.

It’s still unclear what the sweeping measures mean for state-based immigration efforts in Texas. The Legislature is currently debating a bill to outlaw “sanctuary” jurisdictions in Texas, the term commonly assigned to local entities that don’t enforce immigration laws or hand over undocumented immigrants to federal authorities. Since the November election, lawmakers have expressed hope that the new administration would make good on Trump's promises to secure the border but have continued plans to focus on the issue in Austin while Washington fine-tunes its efforts.

Immigrant rights groups immediately blasted the news Tuesday as a mass-deportation campaign that goes against stated promises to only concentrate on criminal aliens.

“Now they are openly admitting that they ‘will not exempt classes or categories of removable aliens from potential enforcement,’” said Lynn Tramonte, the deputy director of America’s Voice Education Fund, an immigrant rights group, in an statement. “These memos amount to an instruction manual for the coast-to-coast, fast-track deportation of everyone in the United States without papers, no matter how long they’ve been here, how strong their family ties, and how much they contribute.”

The memo also calls for immediately hiring 5,000 additional Border Patrol agents, asks Homeland Security to identify all sources of federal aid to Mexico over the last five years and calls for the agency to identify and allocate all sources of available funding for the planning, design, construction, and maintenance of a border wall. Under the new guidelines, all undocumented people approved for deportation will be returned to the country from which they entered illegally instead of where they originally came from. That means Mexico will see an influx of immigrants from Central America and elsewhere who used the country as an entry point into the United States.

On Monday, ProPublica, citing former Mexican and American officials, reported on how that policy shift could create new security issues for the region "as authorities in each country push unwanted migrants back and forth."

Visiting Austin on Tuesday, U.S. Rep. Michael McCaul, R-Austin, defended Trump's actions so far on immigration law enforcement and downplayed their scope. 

"I think, quite frankly, this is not a very large departure from the previous administration because they were, again, prioritizing criminal aliens," McCaul, who chairs the House Homeland Security Committee, told reporters at the Texas Capitol.

"And so I think you’re going to see more of an emphasis on this, and you’re going to see more of an attempt to get people who are in this country, who are not acting in good faith, who are a danger to our public safety, out."

Patrick Svitek contributed to this report.