China marked the anniversary of Japan's brutal occupation Wednesday, as a state-run memorial museum called on Tokyo to offer compensation and an apology to relatives of those forced into manual labour during World War II.

Japanese soldiers blew up a railway in Manchuria 82 years ago, blaming Chinese troops as a pretext to take control of the whole northeastern region, in what became known as the Mukden Incident.

Now the Asian giants are major trading partners, but their political relationship remains soured by Japan's military expansion into China before and during World War II.

They are currently at loggerheads over disputed islands in the East China Sea controlled by Tokyo but claimed by Beijing.

The Museum of the War of Chinese People's Resistance Against Japanese Aggression displayed more than 400 documents it said detailed how 40,000 Chinese were forced to work in Japan during the war.

It also invited relatives of those who died in Japanese captivity, including 79-year-old Lu Cunjie.

His father Lu Mingdao was among 10 people taken to Japan from his village in the northern province of Hebei.

"Only four of them returned," Lu told AFP, after flicking through the documents to find his father's name.

"After Japan surrendered, those four people told me the news... saying that my dad had gone, and his ashes had been thrown into the sea.

"All our family could do was make a living by being supported by relatives and farming the land. We even begged for food.

"Dad's gone, the family was ruined. Every time when I bring it up, I just can't stop crying."

A video played at a media briefing showed what it called "shameless" Japanese politicians visiting the Yasukuni war shrine, which commemorates more than two million Japanese war dead, including 14 Class A war criminals.

Beijing regularly accuses Tokyo of failing to atone for its imperialist past, while Japan says its neighbours use history as a diplomatic stick to beat it with.

Air raid sirens sounded across the country at 9:18 am (0118 GMT) to mark the anniversary and "remind people of the national humiliation", the official Xinhua news agency reported.

The agency said in a commentary that current disputes between China and Japan had their roots in bitter historical relations.

"A walk down the memory lane should serve as a reminder that China and Japan cannot discuss the current strained bilateral relations without mentioning history," it said.

It listed a series of events involving the two countries, starting with the Mukden Incident and ending with Japan's nationalisation of the disputed islands Beijing calls Diaoyu and Japan refers to as Senkaku.

At the museum, its deputy director Li Zongyuan told AFP: "We are going to file lawsuits to the Japanese government to make them admit what they did, apologise and give compensation to the relatives of victims."

Relatives of Chinese who were forced into labour have previously filed claims against Japanese corporations, most of which have failed.

Campaigners showed pictures of emaciated prisoners.

"It's so miserable. They have got this half-man half-ghost look. I think if Japan hadn't lost the war, they would never have had the chance to come back to China alive," said Zhang Enlong, who represents the families fighting for compensation.

Japanese courts have previously said that China relinquished its rights to wartime compensation with the 1972 China-Japan joint agreement, which normalised relations between the two countries.