Washington, Feb 24 (IANS): US President Donald Trump has assigned the Department of Homeland Security (DHS) to help build a legal case for its temporary travel ban on individuals from seven countries, a senior White House official said.

"The DHS and Justice Department are working on an intelligence report that will demonstrate that the security threat for these seven countries is substantial and that these seven countries have all been exporters of terrorism into the US," the official told CNN.

"The situation has gotten more dangerous in recent years, and more broadly, the refugee programme has been a major incubator for terrorism."

The report was requested in light of the Ninth Circuit Court of Appeals' conclusion that the Trump administration "has pointed to no evidence that any alien from any of the countries named in the order has perpetrated a terrorist attack in the US".

The seven counties are Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen.

The official said the desire to bolster the legal and public case that these seven countries pose a threat is a work in progress and, as of now, it is not clear if the DHS and Justice Department will offer separate reports or a joint report.

The official told CNN that one possible way the White House could justify the ban is to include a list of terrorism-related injuries, investigations and other actions in the report.

Trump's order, and a revised version are expected next week.