Originally Published: 27 MAY 19 15:59 ET

Updated: 27 MAY 19 16:24 ET

By Devan Cole and Geneva Sands, CNN

(CNN) -- The head of a union representing US Citizenship and Immigration Services employees on Sunday slammed Ken Cuccinelli, an immigration hardliner who President Donald Trump is expected to tap to lead the agency, saying his potential appointment "spells the end of legal immigration as it currently exists."

"The resignation of Francis Lee Cissna as Director of USCIS and the possible appointment of Ken Cuccinelli as his successor spells the end of legal immigration as it currently exists," Danielle Spooner, the president of the union representing all USCIS employees, said in a statement.

"It has become clear that the goal of this Administration is to end immigration all together. How better to do that then by appointing as the leader of USCIS someone who knows nothing about immigration, Adjustment of Status or Naturalization, and whose sole purpose is to destroy the agency that grants these benefits," the statement read.

Cuccinelli did not immediately respond to CNN's request for comment Monday.

The rebuke comes several days after L. Francis Cissna, the agency's current head, announced he would be stepping down amid a major shakeup in the last month among the leadership at the Department of Homeland Security.

Trump is expected to tap Cuccinelli, a former Virginia attorney general and CNN legal commentator, to be the next director of USCIS, but it has not yet been formally announced, according to a senior administration official. Last week, CNN reported that Cuccinelli was expected to take a top job at DHS to help steer the administration's immigration policies, another senior administration official said.

The President had also previously been considering Cuccinelli to take on the role of "immigration czar," a position Trump had considered establishing to improve coordination between the agencies involved in handling the steep uptick in migrants crossing the US's southern border in recent months.

Earlier this year, the Senate postponed a vote on Trump's pick to lead Immigration and Customs Enforcement, Ron Vitiello, after a union representing ICE officers opposed the nomination. Trump later pulled Vitiello's nomination, saying he wanted to go with someone "tougher."