A Japanese daily says secret documents that state that the U.S. military is free to use military bases in Japan in the event that war breaks out on the Korean Peninsula have been found.

The Yomiuri Shimbun said Friday that the two secret documents that were recently discovered are drafts of a transcript that were written in 1960, when the U.S. and Japan signed a new security treaty.

The report said the documents are likely to spark controversy both in South Korea and in Japan as the documents show that the Japanese government recognizes the mobilization of U.S. troops without prior approval.

The Japanese government has previously denied the existence of secret agreements with the U.S. However, a series of documents have recently emerged that support arguments of the existence of such secret accords. Such documents appeared after the Hatoyama administration launched a probe into alleged secret agreements with the United States days after it took office in September.

Foreign Minister Katsuya Okada said he would hold a news conference next month and shed light on suspicions over the secret pacts.