WASHINGTON, United States (AFP) — US Attorney General Jeff Sessions said Tuesday that national security is being undermined by an immigration system that has allowed hundreds of terrorists to enter, as the White House pressed for a sweeping changes to who can enter the country.

Days after President Donald Trump sparked an uproar reportedly complaining about immigrants from Haiti, El Salvador and Africa as coming from “s***hole” countries, the administration moved to refocus the debate on the links between open immigration and terror threats.

A new report from the Justice and Homeland Security Departments said that nearly three-fourths of the 549 international terror-related convictions in US courts since the September 11, 2001 Al Qaeda attack involved foreign-born individuals, including 148 granted citizenship after arriving in the United States.

“This report reveals an indisputable sobering reality — our immigration system has undermined our national security and public safety,” Attorney General Jeff Sessions said.

“And the information in this report is only the tip of the iceberg: we currently have terrorism-related investigations against thousands of people in the United States, including hundreds of people who came here as refugees.”

The report, the White House said, supports the need to end two key immigration programs: the 28-year-old “green card” lottery system open to immigration hopefuls from around the world, and so-called chain migration, which allows the extended families of immigrants to also come to the United States.

The White House says the current system brings too many people to the country who cannot assimilate and lack skills and education to contribute to society.

“Our properly functioning immigration system promotes assimilation in all its forms, through whatever mechanism by which those individuals come to the United States,” a senior administration official told journalists in a background briefing on the report.

“It doesn’t promote the admission of individuals who are not likely to succeed, who are not likely to assimilate, who could potentially radicalise or may already be radicalised to pose a threat to our national security.”

White House officials say they want a system like Canada’s or Australia’s, where hopeful immigrants are evaluated on what kinds of skills or knowledge they can bring to the country.

They continued to deny that Trump is racist after Democratic lawmakers said he had called several countries “shitholes” in a heated immigration policy debate.

The problems, they said, are the green card lottery and chain migration.

“Every nation continually evaluates its needs,” the senior official said.

The government wants to ensure that the immigration system “serves the national interest”, including by looking at “the likelihood of an individual’s success” after immigrating,” he said.