REUTERS/Kevin Lamarque
He even refused to rule out having Japan and South Korea develop their own nuclear weapons in an interview with Fox News.
In March 2016, before North Korea's nuclear testing had quite reached the fever pitch it's at today, Trump proposed allowing South Korea and Japan to develop their own nukes to protect themselves.
The proposal was widely panned by nuclear-proliferation experts.
But Tillerson now stresses that all options are on the table for dealing with North Korea, and that could include more countries building nuclear weapons.
Daryl Kimball, executive director of the Arms Control Association, told Business Insider the idea that North Korea's nuclear posturing could be answered with further nuclearization of the region was "foolish, simplistic, and naive," and "deeply, deeply troubling."
"If all options are on the table, that should mean that diplomacy and talks with North Korea are on the table," said Kimball, who acknowledged that "Tillerson is right that, up to now, US administrations have not succeded in denuclearizing North Korea."
But the US has refused talks with North Korea and also refused to cancel its military drills with South Korea, which China said Pyongyang would be willing to stop their nuclear program over.
Korean Central News Agency via Reuters
"But it's a pure fantasy for Rex Tillerson to demand that North Korea denuclearize before allowing or agreeing to talks" with Pyongyang, Kimball added, also providing a thorough timeline of diplomatic attempts to curb the rogue nation's nuclear program.
Tillerson, who traveled to Asia without the customary press corps, has raised many questions over the US's intentions in South Korea but provided few answers.
"Tillerson says something new is required. We're at day 57 and this is the most urgent foreign-policy issue we have," Kimball said. "What is the new policy?"