Chinese authorities have moved to quell anti-Japanese protests as Japanese firms suspended work at factories in China over a territorial dispute.
Protests have been growing in China against Japan's claim of ownership over several uninhabited islands called the Senkakus in Japan and Diaoyu in China.
Japan said last week it was purchasing the islands from their private owner.
There have been protests in China over the islands for weeks.
But the announcement that Japan was buying the islands touched off new, often violent demonstrations in Chinese cities over the weekend, mostly targeting Japanese-owned businesses, some of which were vandalized.
Japanese firms such as Panasonic and Toyota, as well as smaller companies and restaurants, were closed on September 17 and the management of those enterprises told employees not to come to work amid confrontational scenes between police and angry demonstrators.
China's government called for protests to be conducted in an "orderly, rational, and lawful" manner.
Beijing also pledged to protect Japanese citizens and property in China.
China has boosted the number of police and security forces guarding Japanese diplomatic representations and businesses in China.
The Japanese Embassy in Beijing was reportedly guarded by some 1,000 security personnel on September 17.
But Chinese Foreign Ministry spokesman Hong Lei told a press briefing that Japan needed to act in a manner that avoided causing further tensions.
U.S. Secretary of Defense Leon Panetta was in Japan on September 17 urging Japan and China to resolve the issue through negotiations.
"We're concerned by the conflict that is taking place over the Senkaku Islands, and the message that I've tried to convey is a message that we have to urge calm and restraint on all sides," Panetta said.
Panetta said no one in the Asian Pacific region benefits from the current rhetoric coming out of Tokyo and Beijing.
"It's in everybody's interest, it is in everybody's interest, for Japan and China to maintain good relations and to find a way to avoid further escalation," Panetta said.
Besides the potential military aspect to the current dispute, countries in the West are concerned the Japanese-Chinese row could further exacerbate the global economic crisis by disrupting trade ties with Asia.
Based on reporting by Reuters, AFP, AP, and dpa