(CNN) The Department of Homeland Security is set to release guidance on President Donald Trump's immigration and border security executive orders that has sweeping implications for undocumented immigrants in the United States and those seeking to enter in the future.

The memos from Homeland Security Secretary John Kelly to agency chiefs, obtained by CNN, are the first step to putting Trump's aggressive immigration policies in place, with provisions that could make substantial changes to how immigration laws are enforced.

The guidance will tighten immigration laws on asylum seekers and unaccompanied minors entering the country and could send individuals awaiting immigration proceedings in the United States back to Mexico.

While the documents do not change anything in the executive orders on border security and interior immigration enforcement that Trump signed during his first week in office, they do explain how the administration plans to put those orders in place, signaling a hard-line position on undocumented immigrants that will please the right wing on immigration policy.

The memos could also further inflame tensions with immigrants, their advocates and Democratic lawmakers who have been highly critical of Immigration and Customs Enforcement's arrests of nearly 700 immigrants nationwide this month. While ICE said 75% of those arrested had criminal records and insisted the "targeted" enforcement was consistent with what the Obama administration had done, the department also said officers who encountered individuals not on the list of targets were given latitude to decide whether they should also be arrested for removal.

Fear in immigrant communities had already been running high based on Trump's pitched rhetoric against illegal immigration on the campaign trail, and only increased during the ICE enforcement actions.

The new guidance makes it more difficult to seek asylum in the US, allows the detention of substantially more undocumented immigrants and gives more authority to immigration officers -- all of which could add up to a huge increase in the number of undocumented immigrants held in detention facilities by the US government.

A department spokeswoman, Gillian Christensen, said she could not confirm the guidance is final and would not comment on documents before they are publicly released, but she did not dispute their contents. The documents have yet to be published and could change before they're officially issued.

On Monday, No. 2 Senate Democrat Dick Durbin put out a statement decrying the new guidelines, calling them "mass deportation" implementation.

"I have called on my counterpart on the Judiciary Subcommittee on Immigration, Chairman John Cornyn, to hold hearings on these orders -- we need an immediate public examination in Congress of these heavy-handed, anti-family policies," Durbin said, calling for legislation he's sponsored repealing Trump's executive orders, which has little hope of advancing.

The border security guidance expands the use of "expedited removal" proceedings for unauthorized immigrants, allowing them to be deported more quickly with limited court proceedings.

In doing so, the memo allows for the quick removal of immigrants who cannot prove they were in the US continuously for two years before being apprehended and determined to be unauthorized.

Previously, ICE and Customs and Border Protection had used "expedited removal" only for immigrants caught within 100 miles of the border within 14 days of entering the US or by those who arrived by sea but not at a port of entry.

The border security guidance also expands upon ending the so-called "catch-and-release" policies that allow individuals to be paroled from detention while awaiting immigration court proceedings, which can take years. The memo orders a surge in immigration judges and detention facilities to accommodate the holding of these individuals and lays out high thresholds for people to be released pending immigration proceedings.

The memo gives room to tighten the standard for meeting the initial "credible fear" test for immigrants to be considered for asylum in the US, a threshold that tens of thousands of asylum seekers now meet each year.

Past Department of Justice guidance has given some leeway to those who perceive a risk of persecution or torture in their home countries. While the memo does not explicitly raise the standard for finding a "significant possibility" that an immigrant could be granted asylum, it places a high bar on whether the perceived threats are credible.

"The asylum officer shall consider the statements of the alien and determine the credibility of the alien's statements made in support of his or her claim and shall consider other facts known to the officer, as required by statute," the guidance states. "The asylum officer shall make a positive credible fear finding only after the officer has considered all relevant evidence and determined, based on credible evidence, that the alien has a significant possibility of establishing eligibility for asylum, or for withholding or deferral of removal under the Convention Against Torture, based on established legal authority."

Further, for immigrants to be released pending asylum proceedings after meeting the credible fear threshold, the memo requires that an ICE immigration officer is satisfied the person "affirmatively establishes" his or her identity and that he or she presents no security or flight risk and agrees to conditions imposed by ICE for public safety reasons.

The guidance also makes it more difficult for children entering the country without authorization to be treated as "unaccompanied alien children." Under the law, the designation is for those under 18 years old who do not have a parent with them or available to care for them in the US.

The executive order notes that in some cases, individuals continued to receive protection as unaccompanied alien children even when they had a parent or guardian living illegally in the US, saying it led to "abuses" of the system. Kelly's memo calls for new guidance to end those "abuses."

The executive order also instructed DHS to enforce of a little-used provision of the law to return asylum seekers to the contiguous territory from which they entered the US, namely Mexico. The measure would potentially send non-Mexican asylum seekers from Central America over the southern border while they await asylum proceedings instead of letting them wait in the US, a policy with which Mexico would likely take issue.

Kelly's memo orders the implementation of that policy and the creation of a video conferencing system to allow those removed individuals to appear at hearings without being brought back into the US.

Significantly, the interior safety order explicitly leaves intact President Barack Obama's executive orders on deferred action for childhood arrivals, known as DACA, which protects undocumented immigrants brought to the US as children from being removed and orders the low prioritization of undocumented immigrants who are parents of US citizens. The memo says, however, that the latter policy "will be addressed in future guidance."

The memo re-articulates Trump's enforcement priorities from his executive order , which prioritizes for the removal certain serious criminals and others posting public safety threats, but it also broadens the scope beyond the Obama administration's measure to include virtually any undocumented immigrant in the US if they are even suspected of a crime.

At the same time, the memo declares: "The Department no longer will exempt classes or categories of removable aliens from potential enforcement," which could imply that those protected by DACA could still be subject to removal proceedings.

The memos also expand what's known as the "287(g)" program, which allows the federal government to empower state and local law enforcement agencies to perform the functions of immigration officers. The language in the memo authorizes the CBP and ICE "to accept state services" on enforcement, but makes no mention of the National Guard, as an early draft reported by The Associated Press on Friday had done.

The memo gives broad leeway to immigration officers to make immediate decisions about whom to arrest and says officers should begin actions against individuals they meet in the course of their official duties.

"This includes the arrest or apprehension of an alien whom an immigration officer has probable cause to believe is in violation of the immigration laws," the implementation guidance reads, giving officers broad authority to arrest those they suspect of being undocumented.

The guidance also takes any money being used by DHS to advocate on behalf of undocumented immigrants to establish the Victims of Immigration Crime Engagement (VOICE) Office, which is mandated by the executive order to report crimes committed by undocumented immigrants and to advocate for victims of those crimes.

This story was updated with additional details.