Anti-Japanese militarism protesters demonstrated in front of the Japanese Consulate General in Hong Kong on Tuesday to mark the 87th anniversary of the Mukden Incident, an event considered as the beginning of Japan's invasion of China.

Protest groups came from across Hong Kong's political spectrum, including one opposed to Japan's control of uninhabited islands in the East China Sea that are known as the Senkakus in Japan and Diaoyu in China.

On Sept. 18, 1931, Japanese military officers blew up a portion of a Japanese-controlled railroad north of what is now Shenyang and blamed it on Chinese dissidents. The incident was used as a pretext for Japan to send troops into China, marking the beginning of a 14-year occupation, historians say.

"Forget not Japan's invasion of China! Forget not Nanking massacre!" activists of the Action Committee for Defending Diaoyu Islands chanted. "No to Japan militarism! Japan must apologize and compensate!"

The group also repeated its call for Japan to leave the Senkaku islets, which are claimed by China and Taiwan. Members of the group landed on one of the islets in 2012 in a bid to declare Chinese sovereignty.

Other protesting groups included the pro-Beijing Federation of Trade Unions and the Taiwan-leaning Generalissimo Chiang Kai Shek Association, which warned against the revival of Japanese militarism by way of an amendment to the war-renouncing Japanese Constitution.

"Japanese Prime Minister Shinzo Abe's attempt to amend the Constitution is a worrying sign of Japanese militarism," said Aron Kwok, a member of the Federation of Trade Unions and a legislator in Hong Kong.