The Foreign Ministry is under fire for mistranslating a key term in Japanese Prime Minister Naoto Kan's apology for colonial rule on Tuesday.

Kan pledged his government will "transfer" historical artifacts seized during the colonial period between 1910 and 1945, but the Foreign Ministry quoted Kan as saying it will "return" them, and even highlighted the word in bold in a press release.

Japan's position so far has been that all claims for restitution were settled under the Korea-Japan Normalization Treaty in 1965. The word "return" would imply that Tokyo now recognizes the illegality of taking the treasures and could open the way for a massive repatriation of looted artifacts. But Japan avoided the delicate issue with the word "transfer."

Japanese Prime Minister Naoto Kan reads a statement on Tuesday morning marking the 100th anniversary of Japan's annexation of Korea. /Yonhap

On Tuesday, a Foreign Ministry official said the word "return" was used "in an unofficial translation of the statement the Japanese government gave us." But on Wednesday it emerged that the translation was apparently made by the Korean Embassy in Japan and not by the Japanese government. "We mistook the translation provided by our embassy in Japan for the official text," another Foreign Ministry official later said.

Critics say that is an unlikely mistake to make. Foreign Ministry spokesman Kim Young-sun on Wednesday said the word "return" "would be appropriate when referring to giving back national treasures that were taken illegally." Some Korean officials tried to downplay the translation error as being a fairly common occurrence in relations with Japan, pointing out that Korea is reluctant to use the word "emperor" for the Japanese monarch, preferring the term "king" instead.

But one Korean diplomat said, "I don't know why the government is trying so hard to embellish something that Japan should have addressed in the first place, even going so far as to mistranslate it."