WASHINGTON: US President Donald Trump has signed a presidential memorandum to set up a 30,000-person migrant facility at Guantanamo Bay to detain "high-priority criminal aliens."

The Guantanamo Bay facility, which has so far been used to hold terrorists, will now also house illegal immigrants with criminal records.

The signing took place on Wednesday, with Trump directing the Departments of Defence and Homeland Security to prepare the facility. According to the memorandum, he ordered the expansion of the Migrant Operations Center at Naval Station Guantanamo Bay to accommodate "high-priority criminal aliens" and address related enforcement needs.

“Most people don't even know about it. We have 30,000 beds in Guantanamo to detain the worst criminal illegal aliens threatening the American people," Trump said at a White House event.

"Some of them are so bad, we don't even trust their home countries to hold them. Because we don't want them coming back, so we're going to send them to Guantanamo,” he said.

“This will double our capacity immediately. It's a tough place to get out of. Today’s signing brings us one step closer to eradicating the scourge of migrant crime in our communities once and for all,” he added.

With this, Trump has ramped up efforts to remove illegal immigrants from the country, a major poll promise.

He said the memorandum was issued to halt the border invasion, dismantle criminal cartels, and restore national sovereignty.