Thousands of protesters took to the streets near the Japanese Consulate in Shanghai Sunday to protest the Japanese government's decision last week to purchase the disputed Diaoyu Islands.

The protest, which was tightly controlled by local police, gave local residents a venue to vent their anger against the Japanese government, while leaving the city's Japanese expatriate population treading carefully.

Local police blockaded the streets surrounding the consulate in downtown Changning district early Sunday morning. "I arrived here early in the morning and the streets had already been blocked off," said Huang Wei, a 17-year-old protester.

Police set up barricades on parts of Loushanguan Road, Xingyi Road and Wanshan Road, where the consulate is located. The surrounding area is not just home to the consulate, but many of the city's 29,700 Japanese expatriates, according to the Shanghai Bureau of Statistics. Japanese are the largest foreign nationality living in the city.

Although protesters congregated in groups of hundreds, police divided them into smaller groups of no more than 100 people, allowing each to stay in the blockaded zone for only a short period of time.

Each group was accompanied by at least three officers as they walked through the blockaded zone, which was lined with dozens of armed riot police carrying batons and shields.

Protesters were only allowed to enter the zone if they came in a group, and  their leaders had to register their identification numbers and phone numbers with police on site. Individuals were prevented from entering the protest zone. "I came here with a friend. We were only allowed inside after we joined a group of about 200 people that was mostly university students and young workers," Huang told the Global Times.

Huang, who works at a local restaurant, found out about the protests in advance on an online forum.

Police confiscated protesters' water bottles, and warned them not to carry any flammable material into the protest area. "You should be careful not to throw anything toward the consulate building. You are not allowed to burn anything. You will be given about 10 minutes to express your feelings in front the Japanese consulate," a police officer told a group of protesters through a bullhorn.

Zhu Mingbo, a young man from Shandong Province who works in a local factory, led a group of about 100 people to the protest. "The Diaoyu Islands belong to China. Japanese get out," Zhu shouted.

He carried a banner that he said he ordered from a printing shop. "The owner only charged me half-price after he learned it was for an anti-Japanese protest," he said.

Zhu said that he came here to rally more people to join a larger protest that is supposed to take place Tuesday, the anniversary of the Japanese invasion of China in 1931.

Surrounding businesses were mindful of the anti-Japanese sentiment. Many nearby Japanese restaurants covered up their signs and stuck up notices that said they were run by Chinese. One notice said: "The Diaoyu Islands belong to China."

Shanghai has seen its share of anti-Japanese protests.

The most significant one took place in March 2005. The demonstrations were sparked by a proposal to grant Japan a permanent seat on the United Nations Security Council.

In February 2009, some 20,000 anti-Japanese protestors also took to the streets over Japan's wartime history, throwing stones at the Japanese consulate and smashing nearby cars and storefronts.

Japan's embassy said two Japanese citizens were injured after being surrounded by a group of Chinese in Yangpu district, according to a report by the Kyodo News agency.

The long-running tension between China and Japan is a recurring and sensitive issue, said Fan Yongming, an international relations professor who specializes in Sino-Japanese relations at Fudan University.

"Japan's actions during World War II scarred relations between the Chinese and Japanese peoples," he said. "These protests occur almost every year around the country, but they usually do not impact Japanese residents' daily lives in Shanghai."

Shanghai's Japanese community has little interaction with the local community, Fan said.

Still, the protests will likely have little impact on the local Japanese population. "With the exception of those who have their own shops or restaurants and may need to tread lightly, few Japanese intend to uproot their lives in Shanghai," he told the Global Times.

Nuri Matisumata, a 37-year-old local Japanese mother, hopes that the anti-Japanese protests will not affect her family's life in the city.

"I have driven my children to school every day since we heard about the anti-Japanese protests across the country," she told the Global Times. "But we are still going to supermarkets and malls on the weekends like we always do."