Japanese Prime Minister Shinzo Abe stuck to vagueness on the country's responsibility for its sexual enslavement of women during World War II, calling the issue "human trafficking" without specifying the perpetrator.

The statement, made in an interview with the Washington Post ahead of his visit to the United States next month, appeared carefully calculated not to deviate from his administration's existing position not to unequivocally acknowledge Japan's responsibility for the atrocity.

That dampened hope for a clear apology from Abe when he addresses the U.S. Congress.

"On the question of comfort women, when my thought goes to these people, who have been victimized by human trafficking and gone through immeasurable pain and suffering beyond description, my heart aches," Abe said in the interview held Thursday.

"And on this point, my thought has not changed at all from previous prime ministers. Hitherto in history, many wars have been waged. In this context, women's human rights were violated. My hope is that the 21st century will be the first century where there will be no violation of human rights," he said.

These remarks were similar to a previous Abe statement on the issue, in which he only said without issuing an apology that he was "deeply pained to think of the comfort women." Rather than such vague statements, critics have said Japan should issue a clear apology as the perpetrator.

Abe also said during the interview that his cabinet upholds the position on the recognition of history of the previous administrations, in its entirety, including the Murayama Statement in which the country apologized for the imperialistic past.

He also said his government is not reviewing the Kono Statement of apology for the sexual slavery.

Abe will become the first Japanese prime minister to address a joint session of Congress.

Critics have claimed that Abe is not worthy of the honor because he has attempted to whitewash Japan's militaristic past and wartime atrocities, especially the sexual slavery issue, while refusing to acknowledge the country's responsibility and compensate victims.

Korean-American organizations have campaigned against such an address by Abe and collected thousands of signatures. They also ran a full-page advertisement in a Washington-based newspaper demanding Abe apologize for the sexual slavery issue before speaking before Congress.

Historians estimate that up to 200,000 women, mainly from Korea, which was a Japanese colony from 1910 to 1945, were forced to work in front-line brothels for Japanese soldiers during World War II. But Japan has long attempted to whitewash the atrocity.

The sexual slavery issue has been the biggest thorn in frayed relations between Japan and South Korea, with Seoul demanding Japan take steps to address the grievances of elderly Korean victims of the atrocity and Japan refusing to do so. (Yonhap)