The possibility of a nuclear-armed Japan has again been raised by the Trump administration, after U.S. Secretary of State Tillerson appeared to say in an interview ahead of his visit to Beijing that, with "all options on the table" regarding the North Korean threat, "circumstances could evolve" in terms of Tokyo acquiring atomic weapons.

In an interview Saturday with the lone reporter allowed to accompany him on his visits to Japan, South Korea and China, the top U.S. diplomat, who had previously dismissed the need for Tokyo and Seoul to acquire nuclear weapons, was asked if his views had shifted, given the surging tensions on the Korean Peninsula.

"We say all options are on the table, but we cannot predict the future," Tillerson replied. "So we do think it is important that everyone in the region has a clear understanding that circumstances could evolve to the point that for mutual deterrence reasons, we might have to consider that."