The United States said on Monday that Japan should act "in a forthright and responsible manner" for its role in sex slavery committed by the Japanese army during World War II.

"We certainly would want to see the Japanese continue to address this and to deal with it in a forthright and responsible manner that acknowledges the gravity of the crimes that were committed," State Department deputy spokesman Tome Casey said at a briefing.

As to the apology by Japanese Prime Minister Shinzo Abe over the wartime sex slaves, Casey said: "We appreciate that the apology was made. It is a step forward."

Earlier Monday, Abe apologized "as the prime minister" to the wartime sex slaves.

"I am apologizing here and now as the prime minister," Abe told a parliamentary committee in response to a question by a lawmaker from the Japanese Communist Party.

"I feel sympathy for the people who underwent hardships, and I apologize for the fact that they were placed in this situation at the time," Abe said.

Earlier this month, the Japanese prime minister denied there was any evidence to establish that Japan's military authorities or government officials were directly involved in forced sex slavery during World War II, which immediately drew international criticism and concern.

An estimated 200,000 women were forced to serve as sex slaves for Japanese forces during World War II, and most of them came from countries invaded by Japan at the time.

Source: Xinhua