By Andy Sullivan and Roberta Rampton

WASHINGTON (Reuters) – President Donald Trump plans to remove more top leaders of the U.S. Department of Homeland Security (DHS), an official familiar with the matter said on Tuesday, as a senior administration official said agency leaders have not done enough to crack down on a surge in immigration.

The department’s acting No. 2 official, Claire Grady, could leave as soon as Tuesday afternoon, the source said.

Administration officials were also trying to push out the department’s General Counsel John Mitnick, and U.S. Citizenship and Immigration Services Director Francis Cissna, said the source, who spoke on condition of anonymity.

Trump denied that he was overhauling DHS and said his administration was fighting “bad laws” on immigration.

“Nobody ever said I was cleaning house,” Trump told reporters at the White House.

Homeland Security Secretary Kirstjen Nielsen announced her resignation on Sunday after a meeting with Trump in which the two disagreed on the best way to handle border security.

The personnel changes could further destabilise the U.S. domestic security agency as it tries to stem rising numbers of immigrants arriving at the border, many of them families fleeing violence and poverty in Central America, that swelled last month to the highest in a decade. Trump campaigned on a promise to restrict immigration and has made it a central focus of his presidency.

The U.S. Secret Service said on Monday that its chief Randolph “Tex” Alles would depart his job next month, and Trump last Friday withdrew the nomination of Ronald Vitiello to serve as director of U.S. Immigration and Customs Enforcement.

A senior administration official, speaking on condition of anonymity, said political appointees at the agency have failed to draft regulations and make other changes that could have prevented a surge of migrants seeking asylum along the U.S.-Mexico border.

The official singled out Citizenship and Immigration Services as “the biggest bottleneck” in changing immigration rules, but declined to comment about possible personnel changes at that agency or DHS’s legal office.

U.S. Customs and Border Protection Commissioner Kevin McAleenan is due to take Nielsen’s place on a temporary basis, starting on Wednesday.

Trump has interviewed several candidates for the top job over the past week and a half, including former Kansas Secretary of State Kris Kobach, former Virginia attorney general Ken Cuccinelli, and former acting Immigrations and Customs Enforcement head Thomas Homan.

All three have expressed hard-line views on illegal immigration, and could have difficulty winning confirmation in the U.S. Senate, which Trump’s Republicans control by a 53-47 margin.

(Reporting by Andy Sullivan and Roberta Rampton; additional reporting by Makini Brice and Jeff Mason; Editing by Kevin Drawbaugh and Grant McCool)