MANILA, April 21 (Xinhua) -- Japan is undermining regional stability by returning its combat troops to Philippine soil for the first time in 81 years since the end of World War II, a Filipino expert said.

"Japan's right-wing government towards aggressive militarization is a foreboding of imminent dangers to the peace, stability and prosperity of the Asia-Pacific region, including the Philippines," Herman Tiu Laurel, president of a Manila-based think tank, told Xinhua in an exclusive interview.

As the Philippines and the United States kicked off their annual Balikatan military exercises on Monday, Japan, no longer merely an observer, has dispatched over 1,000 combat troops to participate in the largest-ever Philippines and U.S.

military drills, in which over 17,000 troops are engaged.

"The return of Japan's combat forces to the Philippines poses blatant challenges to the outcomes of the World Anti-Fascist War victory," Laurel said.

Following the outbreak of WWII, Japan occupied the Philippines in 1942.

Since then, the Japanese forces committed a litany of atrocities, including the Manila Massacre, the Bataan Death March and the forced recruitment of "comfort women," a system of sexual slavery, claiming the lives of over a million Filipinos.

Laurel noted that the Japanese authorities have recently actively demanded that the Self-Defense Forces be enshrined in the Constitution, while continuously expanding its armaments and advocating possession of nuclear weapons.

"These signs of the resurgence of right-wing forces could become a 'ticking time bomb' for....