Japan will prepare to send troops to the Korean peninsula to protect its nationals there if a crisis requires their evacuation, its defence chief reportedly said Tuesday.
The remarks by Defence Minister Tomomi Inada came as fears grow over North Korea, which is believed to be on the verge of a sixth nuclear test and has threatened to launch missile tests "every week".
But her statement in parliament reported by Jiji Press and public broadcaster NHK is likely to be controversial in South Korea.
There memories of Japan's brutal colonial occupation from 1910-1945 have hindered relations and the possibility of Japanese troops on its soil would likely cause anger.
Inada, a noted hawk who supports a bigger role for Japan's military, said that the country would be ready to mobilise its troops if Japanese needed to be evacuated "but have difficulties in leaving via private means of transportation".
Inada said such a dispatch of troops is allowed under Japanese law, which also requires the consent of the related country.
Japan's constitution renounces the right to wage war and the country's military is limited to self defence in the strictest sense.
Prime Minister Shinzo Abe, however, is pushing to expand the military's role and legislation was passed in 2015 that could see troops engage in overseas combat for the first time since the end of World War II.
Inada's comments came as US Vice President Mike Pence arrived in Japan after visiting South Korea, the first leg of his Asian tour, and observed the Demilitarized Zone separating the two Koreas.
Pence met Abe on Tuesday, reiterating Washington's commitment to their decades-old alliance.