Even before a United States Congressional panel overwhelmingly passed a resolution on Tuesday urging Japan to apologize for its wartime sex slavery, the Japanese government said it would have no comment.

But the vote of 39 to 2 by the House Committee on Foreign Affairs has set the stage for an adoption by the full House of Representatives next month, at which point Prime Minister Shinzo Abe will face pressure to respond in some way or another.

Already Mr. Abe, who initially said Japan would not apologize even if the resolution passed, has quieted his defiance in a bid to minimize its impact. In a news conference before the vote, Mr. Abe said he had no comment on the resolution, saying only that ties between Japan and the United States were “unshakable.”