Police in China have warned people not to attend unauthorised anti-Japanese rallies this weekend, amid a mounting dispute over history and oil fields.
Beijing still bears the scars of last weekend's violent protests
"Express your patriotic passion in an orderly manner," police said.
Chinese officials are wary of a repeat of last weekend's violent protests in Beijing, which angered Tokyo and led to escalating bilateral tensions.
In a bid to defuse the situation, Japan's Foreign Minister is due in the Chinese capital for talks on Sunday.
"I want the Chinese people to recognise and understand Japan-China relations are being negatively impacted" by the protests, Nobutaka Machimura told reporters on Friday.
In New York UN Secretary General Kofi Annan also called for reconciliation between the two sides.
"I hope this issue will be handled in a manner that will not escalate. I rely on the wisdom of the two countries to find a way out," he said.
Chinese activists have posted notices on popular anti-Japanese websites and internet forums, calling for more protests this weekend in Beijing, Shanghai and other cities around China.
Mobile phone messages are also being used to persuade people to take part.
But the authorities have issued warnings to potential participants.
"We hope people and young students can trust that the party and the government can properly deal with Sino-Japan relations... and do not do anything that will affect social stability and hurt the capital's image, " a spokesman for the Beijing Public Security Bureau told the China News Service.
"Any situation that endangers public security or seriously harms social order will be considered illegal behaviour," the bureau added in a statement.
Beijing was criticised by Tokyo after last weekend's unrest, for not doing enough to stop the violence against Japanese-owned buildings in Beijing.
Correspondents said the scale of the disturbance was unusual for China, and indicated tacit official support for the protesters.
Ahead of more possible demonstrations, Japan urged its nationals in China to keep a low profile.
"Please be fully careful to secure your own safety," the Consulate-General of Japan in Shanghai said in a statement on Thursday.
War of words
Last weekend's protests were triggered by Tokyo's approval of school history textbooks which critics say play down Japan's wartime brutality.
The protests were also directed at Tokyo's bid for a permanent UN Security Council seat.
The rallies triggered a war of words between China and Japan, with Tokyo demanding an apology and compensation for the protests, while China told Japan to "face up to history" and admit the suffering caused by World War II.
On Wednesday, Japan further angered China by issuing drilling rights for oil and gas in a disputed area of the East China Sea.
Chinese Foreign Ministry spokesman Qin Gang called the decision a "serious provocation to the rights of China and the norm of international relations".