The U.S. Senate approved a spending bill Thursday that has drawn unexpectedly huge attention from Northeast Asian nations for the inclusion of report language on Japan's wartime sex enslavement of Korean and other Asian women.

President Barack Obama is expected to sign it into law on Friday.

A nonbinding document attached to the Consolidated Appropriations Act for Fiscal Year 2014 calls on the secretary of state to step up efforts to get Japan to apologize for forcing as many as 200,000 women to provide sexual services for its troops during World War II.

The victims are euphemistically called "comfort women."

It is the first time that the issue has been addressed in U.S. legislation.

The House of Representatives passed the spending bill on Wednesday.

In 2007, the House passed a resolution calling for the Japanese government to offer an apology for the wartime atrocity.

The new initiative by the U.S. Congress is expected to increase political pressure for Secretary of State John Kerry on his diplomacy on Japan. (Yonhap News)