South Korea has retaliated against Japan’s “irrational and excessive” request for Korean visitors to voluntarily self-quarantine upon arrival as measures to contain the novel coronavirus epidemic threatened to exacerbate bilateral tensions.

South Korea plans to raise its travel advisory for Japan to Level 2, or “refrain from travel,” First Deputy Foreign Minister Cho Se-young said in a statement late Friday. It also plans to halt a visa-waiver program for Japanese starting Monday and introduce a mandatory two-week quarantine period for any visitors from the country, in response to similar measures imposed by Tokyo in connection with the outbreak.

The South Korean Ministry of Foreign Affairs expressed “deep regret” over Japan’s latest travel restrictions in a statement the same day, saying they came “without prior or sufficient discussion with us, and we strongly urge these measures be immediately withdrawn.” The ministry hinted at deeper mistrust between the two sides as well, saying “we cannot help but be suspicious of a separate intention other than prevention of the virus.”