The Government Accountability Office reported that Acting Secretary of Homeland Security Chad Wolf and deputy Ken Cuccinelli have assumed their positions through an "invalid order of succession" under the Vacancies Reform Act.
Following DHS Secretary Kirstjen Nielsen's resignation in April 2019, Kevin McAleenan assumed the role of acting secretary, who had "not been designated in the order of succession to serve upon the secretary's resignation," the office declared.
"Because the incorrect official assumed the title of Acting Secretary at that time, subsequent amendments to the order of succession made by that official were invalid and officials who assumed their positions under such amendments, including Chad Wolf and Kenneth Cuccinelli, were named by reference to an invalid order of succession," according to the report.
The office has submitted the report to the DHS inspector general, and additional actions could be determined by Congress, to which the GAO reports.
The Justice Department's Office of Legal Counsel is reviewing the report.
DHS did not respond to The Independent's request for comment.
The president has repeatedly circumvented the appointment confirmation process and Senate hearings by placing officials into acting roles. There have not been any DHS confirmation hearings following Ms Nielsen's departure. Nearly a third of 27 top roles at the department are filled by an acting official, including those leading Immigration and Customs Enforcement, Customs and Border Protection and US Citizenship and Immigration Services.
Senate Minority Leader Chuck Schumer said the president's "efforts to install political sycophants to implement his extreme policies in an end run around the law and Senate have finally caught up with him."
Acting Secretary Wolf, who has forged a hardline and violent response to Portland's police brutality protests in tandem with the administration's "law and order" rhetoric and anti-immigration efforts,
Mr Cuccinelli, whose title is Senior Official Performing the Duties of Deputy Secretary of Homeland Security, has served as the acting director of US Citizenship and Immigration Services, a position that a federal judge has ruled was illegal and prohibited him implementing stringent asylum rules.
House Homeland Security Committee chair Bennie Thompson and oversight committee chair Carolyn Maloney have demanded that the men resign from their roles.
"In light of this decision, Mr Wolf should immediately step down and return to his Senate-confirmed position as Under Secretary for Strategy, Policy, and Plans," the chairs said in a statement. "The President should appoint an a political career official to run the department temporarily and follow the Constitution by swiftly nominating a permanent Secretary."
The chairs called Mr Cuccinelli "a political pundit plucked by the president to serve in multiple senior roles at DHS for which he is woefully unqualified."
"GAO's damning opinion paints a disturbing picture of the Trump administration playing fast and loose by bypassing the Senate confirmation process to install ideologues," the chairs said.