Japan's foreign ministry also advised its nationals not to get involved in any trouble by staying away from protest sites.
The advice came after bilateral relations plunged to their lowest levels in recent decades over a trade row stemming from Japan's wartime use of Koreans as forced labor during its 1910-45 colonial rule of the Korean Peninsula.
Last week, Japan's Cabinet approved a proposal to strip South Korea from a list of countries subject to preferential trade status following its July 4 imposition of curbs on exports of high-tech materials to South Korea.
The Japan moves are widely seen as retaliations against last year's South Korean Supreme Court rulings ordering Japanese firms to compensate South Korean victims of forced labor.
Japan has lashed out at the rulings, claiming that all reparation issues stemming from its colonial rule were settled under a 1965 government-to-government accord that normalized bilateral relations. (Yonhap)