A group of historians said Tuesday in Tokyo they have discovered seven official trial documents suggesting the Japanese military directly forced women to work at some of their frontline brothels in Indonesia, China, East Timor and Vietnam.

The documents were produced and submitted by the Dutch, French and Chinese governments to the International Military Tribunal for the Far East, widely known among Japanese as the Tokyo Trial.

The seven documents, which the tribunal adopted as evidence, eventually led to the Japanese military's actions being recognized as a war crime in a chapter on atrocities that was included in the tribunal's 1948 judgment, the scholars from the Center for Research and Documentation on Japan's War Responsibility said at a news conference at the Foreign Correspondents' Club in Japan.

The seven-document discovery may embarrass the Cabinet of Prime Minister Shinzo Abe as well as other conservative lawmakers who recently said there is no evidence proving the Japanese military was directly involved in "forcibly taking" women to military brothels.

"The Special Naval Police (Tokei Tai) had ordered to keep the brothels supplied with women; to this end they arrested women on the streets and after enforced medical examination placed them in the brothels," one document, titled Prosecution Document No. 5330, says. The report on "comfort women" in western Borneo was prepared by the Netherlands Forces Intelligence Service.

"Women who had had relations with Japanese were forced into there brothels, which were surrounded by barbed wire. They were only allowed on the streets with special permission," the document says.

The seven documents were initially made public at the war crimes trial from 1946 to 1948. Parts of three of them were briefly reported on by the Asahi Shimbun in 1997. Many former comfort women have given public testimony about similar experiences with coercion at military brothels.

But little of the seven trial documents -- officially prepared by three non-Japanese governments and used as evidence -- had been revealed to the public until now, which is why the war study center held Tuesday's news conference, said Hirofumi Hayashi, a professor at Kanto-Gakuin University and a research director at the center.

"I organized a brothel for the soldiers and used it myself," Lt. Seidai Ohara of the Japanese military was quoted in Prosecution Document No. 5591, dated Jan. 13, 1946.

Ohara was being interrogated about a case in Moa Island, Indonesia. Some of the women were unwilling to work in the brothel but were forced to do so anyway because they were the daughters of the men who attacked the Kempei Tai (Japanese military police), he said.

Hayashi said at the news conference that "the (postwar) Japanese government accepted the war criminal trial with Article 11 of the peace treaty" that was signed to end the postwar Occupation in 1951.

"Thus the Japanese government must admit the coercion and criminality of the comfort women system," Hayashi said.