AFP-- Applicants from 11 countries, unnamed but understood to include 10 Muslim-majority nations plus North Korea, will face tougher "risk-based" assessments to be accepted.

"It's critically important that we know who is entering the United States," said Homeland Security Secretary Kirstjen Nielsen.

"These additional security measures will make it harder for bad actors to exploit our refugee program, and they will ensure we take a more risk-based approach to protecting the homeland."

The 11 countries, hit with a ban in October in the Trump administration's revised refugee policy, have not been identified officially.

But refugee groups say they comprise Egypt, Iran, Iraq, Libya, Mali, North Korea, Somalia, South Sudan, Sudan, Syria and Yemen.

- Not a 'Muslim ban' -

Speaking anonymously, a senior administration official told journalists that the policy of enhanced security assessments for the 11 countries was not designed to target Muslims.

"Our admissions have nothing to do with religion," the official said, adding that there is "nothing especially novel" about tougher screening for countries deemed to have a higher level of risk.

Donald Trump has pursued a much tougher stance on immigrants and refugees from all countries since becoming president one year ago.

His predecessor Barack Obama set refugee admission in fiscal 2017, which began on October 2016, at 110,000.

When Trump took office a year ago, he slashed that to 53,000, a number that was cut again to a maximum of 45,000 in fiscal 2018.

But refugee arrivals this year could come in significantly lower than that, due to the backlog from the 120-day halt and a slowdown in processing because of generally tougher applicant reviews.

DHS would not explain what the tougher vetting measures for the 11 countries would include.