|The row over the disputed islands have sparked the biggest row between the two countries in years [AFP]
Thousands of people in China and Japan have taken part in tit-for-tat protests over a series of disputed uninhabited islands in the East China Sea
Japanese groups rallied against China's "invasion" of the islands on Saturday, as protesters in three Chinese cities chanted angry slogans about the Japanese.
The demonstrations came despite moves by the two Asian giants to patch up a row sparked last month when Japan detained a Chinese fishing boat captain near the islands known as Senkaku in Japanese and Diaoyu in Chinese.
The islands lie between Japan's Okinawa island and Taiwan.
In Tokyo, Japanese flags fluttered in a park as more than 1,000 people gathered for the second major rally since the maritime incident.
Banners carried such messages as "Japan is in danger!" and "Don't forgive invader China".
As demonstrators left the park and started a march, two young men, believed to be Chinese, sat in the street to stop the rally.
One of their banners read: "Stop fuelling harassment towards Chinese residents in Japan".
The two scuffled with Japanese nationalists and were dragged away by police officers. They were immediately released, according to police.
At the start of the rally, Asako Ogura, a lawyer who belongs to the conservative Sunrise Party, drew large cheers as she took up a microphone to claim China had been ungrateful to Japan.
"We Japanese have long extended official development assistance by using taxpayers' money, and the Chinese economy has grown to surpass the Japanese," she said.
"But China used its economic power to build up its military and now demands we hand over Senkaku and Okinawa on the back of the military power.
"Our fathers and mothers boldly fought Western powers 60 years ago. Now let's fight the Chinese communists and their puppet government led by the Democratic Party of Japan!"
Organisers estimated the crowd at more than 3,200 people, and said internet broadcasts of the event drew 10,000 viewers. The rally continued to the Chinese embassy, where demonstrators delivered a statement, organisers said.
Meanwhile, in China thousands of protesters marched in at least three cities to vent their anger at Japan, state media and witnesses said.
The demonstrators in Xian, Chengdu, and Zhengzhou shouted slogans asserting Chinese sovereignty over the islands and calling for boycotts of Japanese goods, the state-run Xinhua news agency
Some protesters had learned about the planned demonstrations on the internet, it said, but added that the protests were peaceful and watched closely by police.
"About 10,000 youths marched down the street outside our shop," a woman in Zhengzhou, capital of the central province of Henan, told the AFP news agency by phone.
"The were shouting 'Defend the Diaoyu islands' and "Boycott Japanese goods,'" said the woman, who declined to give her name.
Xinhua said at least 2,000 people marched in Chengdu, capital of Sichuan province in the southwest unfurling banners and shouting similar slogans.
In Xian, capital of northwestern Shaanxi province, thousands of college students staged a similar march, it said. Japan is still widely resented in China for its brutal second world war invasion and occupation of parts of the country.
A much smaller group of protesters held a demonstration in Beijing last month as the dispute flared but police kept it under tight control.
The Chinese captain was released last month and the two close trading partners have since moved to thaw relations, with China releasing the last of four Japanese men held for allegedly filming a