President Trump has directed top officials to execute the most aggressive changes in immigration policy since his inauguration, sources tell Axios. Some officials consider the moves legally and politically dubious.

The bottom line: The new policies, which the administration wants to impose using executive authority following the ouster of Homeland Security Secretary Kirstjen Nielsen, would be even more restrictive than those of his first two years.

Asked whether to expect an acceleration in deportations, a senior administration official, familiar with internal deliberations, said: "Yes, that’s the critical part of restoring integrity to the system."

The changes, outlined by the senior official:

1. Make regulatory changes that make it "more difficult for low-skilled immigrants ... to gain admission" into the United States "and easier for high-skilled immigrants who are likely to be self-sufficient."

The Trump administration has produced a draft regulation for this, but it hasn't been finalized.

2. Make it more difficult for people to invoke their fear of returning to their home country in order to seek asylum in the U.S.

The official said the new DHS would "apply greater rigor and scrutiny to these [asylum] claims rather than credulously accepting what's said."

said the new DHS would "apply greater rigor and scrutiny to these [asylum] claims rather than credulously accepting what's said." The official said the State Department could "produce an analysis" comparing an asylum-seeker's claims "against the actual conditions in their home country."

3. The official said the White House is frustrated by the granting of work permits to asylum seekers so soon after entering the country, describing the practice as "a major draw."

The official described previous U.S. practice as "charity toward all, malice toward none."

4. The White House also wants to change rules to allow the government to detain migrant children for longer than the 20-day limit allowed under the so-called Flores agreement.

The Trump administration has produced a draft regulation for this, but it hasn’t been finalized.

The planned policy changes will face enormous challenges, legally and politically.

Reality check: Two of the biggest attempts by the Trump administration to implement policies to curb asylum — a proclamation to prevent anyone who crossed the border illegally from receiving asylum and the “remain in Mexico” policy — were ultimately blocked in court.

Trump's decision to oust Nielsen was born out of the president’s deep frustration with her reluctance to implement major policy changes, according to senior administration officials with knowledge of the president’s thinking.

This included what Trump viewed as her failure to stop a large number of people from seeking asylum in the U.S., or to dramatically cut back on the number of poor and low-skilled migrants coming to the U.S.

what Trump viewed as her failure to stop a large number of people from seeking asylum in the U.S., or to dramatically cut back on the number of poor and low-skilled migrants coming to the U.S. Trump was also frustrated at what he perceived to be the slow speed of deportation of people in the U.S. illegally.

frustrated at what he perceived to be the slow speed of deportation of people in the U.S. illegally. A second senior official added that part of Homeland Security's problem was that it was “woefully understaffed” under Nielsen.

The other side: Sources close to Nielsen tell us that Trump and senior policy adviser Stephen Miller have called for changes that are legally dubious and would therefore be operationally ineffective.

Nielsen has found Trump's demands unreasonable, and he has privately described her as "weak on the border," even though she oversaw actions that many viewed as the most brutal in recent memory — such as the "zero tolerance" policy that separated migrant parents from their children.

Trump's demands unreasonable, and he has privately described her as "weak on the border," even though she oversaw actions that many viewed as the most brutal in recent memory — such as the "zero tolerance" policy that separated migrant parents from their children. These sources say that Trump’s desire to make it dramatically harder for people to seek asylum in the U.S. wouldn’t produce lasting changes because they would immediately lead to court challenges.

Capturing the view of people close to Nielsen, Thad Bingel, a senior homeland security official under George W. Bush, told the NY Times: