Trump pressured Nielsen to release detained immigrants into so-called sanctuary cities

The Trump administration pressured the Department of Homeland Security to release immigrants detained at the southern border into so-called sanctuary cities in part to retaliate against Democrats who oppose President Donald Trump's plans for a border wall, a source familiar with the discussions told CNN on Thursday.

Trump personally pushed Homeland Security Secretary Kirstjen Nielsen to follow through on the plan, the source said. Nielsen resisted and the DHS legal team eventually produced an analysis that killed the plan, which was first reported by The Washington Post.

The proposal is another example of Trump's willingness to enact hardline immigration policies to deliver on border security, a key issue for his political base. Thursday's reports come as the President has amplified his rhetoric on illegal immigration in recent weeks, even threatening to close the southern border if Congress and Mexico don't take action.

White House senior adviser Stephen Miller urged senior DHS officials to make the plan a reality, the source said. The plan finally died after Miller and other White House officials pushed it in February, according to the source.

Miller was angered that DHS lawyers refused to produce legal guidance that would make the plan viable, saying the proposal would likely be illegal.

DHS officials believe that the legal standoff is one reason why Miller has pushed for the firing of John Mitnick, the general counsel for DHS, who is still with the department.

A separate DHS official confirmed there was such a proposal. "These are human beings, not game pieces," the official said.

Asked to comment, a DHS spokesperson said, "This was a suggestion that was floated and rejected, which ended any further discussion." Another DHS official briefed on the matter disputed that the proposal reached Nielsen.