President Donald Trump sought to evacuate U.S. military families from South Korea ahead of the Winter Olympics in February, sources told CNN, a clear indication the president thought war with North Korea was a grave possibility.

"It was an order; it wasn't, 'I'm thinking about it,'" one senior administration official told CNN of Trump's directive. "We saw it as a done deal."

Defense Secretary James Mattis and chief of staff John Kelly convinced Trump to a scaled-down directive that would avoid the evacuation of 8,000 military dependents, including barring military personnel from bringing their families to South Korea during future tours.

"All chaos would have broken out," Jung Pak, a former CIA official and deputy national intelligence officer at the National Intelligence Council, told CNN. "This would have been a sure signpost for Kim (Jong Un) that the US was preparing for a military attack."

The report comes as North Korea canceled a high-level meeting with South Korea and threatened to scrap a historic summit next month between Trump and North Korean leader Kim Jong Un over military exercises between South Korea and the U.S. that Kim has long claimed are invasion rehearsals.

The U.S. will "have to undertake careful deliberations about the fate of the planned North Korea-U.S. summit in light of this provocative military ruckus," the South's Yonhap news agency quoted the North's official news agency KCNA as saying.

South Korea President Moon Kae-in brokered talks between Washington and Seoul during the Winter Olympics, and then met with Kim in the Demilitarized Zone last month. The Trump-Kim summit is due in Singapore on June 12.