U.S. Defense Secretary Chuck Hagel (L) attends a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

U.S. Defense Secretary Chuck Hagel (L) attends a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

Japanese Defense Minister Itsunori Onodera attends a press conference with U.S. Defense Secretary Chuck Hagel following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

U.S. Defense Secretary Chuck Hagel (L) attends a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

U.S. Defense Secretary Chuck Hagel (L) attends a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

U.S. Defense Secretary Chuck Hagel (L) attends a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)

U.S. Defense Secretary Chuck Hagel (R) leaves after a press conference with his Japanese counterpart Itsunori Onodera following their meeting at the Pentagon in Washington D.C., capital of the United States, April 29, 2013. (Xinhua/Wang Yiou)