HOUSTON, Dec. 27 (Xinhua) -- Japanese Prime Minister Shinzo Abe's visit to Pearl Harbor, Hawaii, is meaningless unless he recognizes Japan's war crimes, a well-known Houston expert said Monday.

"Abe's visit to Pearl Harbor, Hawaii, is meaningless unless he recognizes Japan's war crimes and his speech on peace and stability is empty talk unless Japan denounces once and for all its shameful past of militarism and aggression," Peter Li, a professor at the University of Houston, told Xinhua.

Describing Abe's refusal to apologize for the attack on Pearl Harbor as "not surprising," Li said that "this refusal to admit Japanese crimes against humanity has been shown in Tokyo's policy towards Asian countries that were victims of the Japanese aggression."

"This refusal to admit crimes was also demonstrated in its denial of the use of Asian women as 'sex slaves' for the Japanese army and its denial of its war crimes in Nanking, China," he said.

He pointed out that "Japan owes the American people, the Chinese people, and other Asian peoples a sincere apology for its war crimes against humanity."

On Dec. 7, 1941, Japan launched a surprise attack on Pearl Harbor, a U.S. naval base, where thousands of U.S. sailors and marines were killed.

Currently, Abe is in Hawaii and he will take part in a remembrance ceremony at the USS Arizona monument on Tuesday with U.S. President Barack Obama to honor those who died at Pearl Harbor 75 years ago.

Abe's visit came seven months after Obama's trip to Hiroshima in Japan, during which he became the first sitting U.S. president to visit the site where the United States dropped a nuclear bomb in 1945.