A spurt of violence in the Crown Heights section of Brooklyn has left residents wondering if the racial tensions of the past are making a return to the neighborhood, which saw anti-Semitic riots by blacks in August 1991. The first incident in the recent upswing, in which a young black man was badly beaten by Jewish youths, was followed by an attack on a Jewish teenager as he rode his bike a few weeks later. Angry Jewish residents have since taken to the streets with signs reading: "Jewish blood is not cheap!" and "Every Jew a .22." "The kid was throwing rocks at Jews," Shaya Rubinstein, a Lubavitcher and one-time Crown Heights resident now living in Jerusalem, said Monday. "It didn't just come out of nowhere. I was in Crown Heights a few weeks ago, and people were talking about it; there were even more police out on the streets. Who's causing the tension? I don't know. But it's there." Police officers and surveillance cameras have been positioned in larger numbers on corners, and NYPD Commissioner Raymond Kelly paid a visit to the neighborhood earlier this month. In addition, two Jewish groups claiming hundreds of volunteers patrol the streets on foot and by car. The mainly West Indian, African American and hassidic residents are waiting to see what comes next, as others play down the violence as a passing spike in otherwise normal relations. "There's no racial tension in Crown Heights," said Yossi Frankel, an officer with the Shomrim, one of the Jewish groups that patrols the neighborhood. "Both communities are blowing it out of proportion," Frankel said. "There have been incidences, but we're out on the street with police making sure that nothing gets out of hand. Crown Heights is still safe, the way it always has been." But Crown Heights hasn't always been safe. "It's a very delicate situation in Crown Heights, a bubble of tension," said Geoffrey Davis, a longtime resident who is black. "One small incident could escalate into something beyond our grasp," warned Richard Green, head of the Crown Heights Youth Collective, a group he said inspires the races "to interact instead of react." Brooklyn District Attorney Charles Hynes accused Shmira, a second Jewish street patrol organization, of vigilantism and compared it to gangs such as the Bloods and Crips. "It's not going to sort itself out," said Tali Frankel, Yossi's brother and an employee at a local bookstore. "It's been like this for years." "I don't think it's really racial tension," said Frankel's wife, Chani. "It's just kids that have nothing to do, causing trouble." Still, two distinct groups of residents pass each every daily on the sidewalks and brownstone-lined streets. Both communities largely keep to their own, and a certain resentment has boiled below the surface for years. The tensions erupted into all-out rioting in 1991, after a seven-year-old Guyanese boy named Gavin Cato and his cousin Angela Cato, also seven, were accidentally hit by a station wagon in the Lubavitcher rebbe's motorcade. The violence lasted three days and caused large amounts of damage to homes. When it was over, the boy had died of his injuries in the hospital, and Yankel Rosenbaum, a 29-year-old University of Melbourne student in the US conducting research for his doctorate, died after being stabbed by a black mob purportedly yelling: "Kill the Jew!" In the 1920s, the neighborhood had a largely Jewish population, including members of several hassidic groups, and other Orthodox and secular Jews, who had arrived from Europe. When the neighborhood continued to change demographically in the '60s, many Jews decided to leave. However, bound by adherence to their spiritual leader, Rabbi Menachem Mendel Schneerson, the Chabadnikim stayed. "The rebbe blessed the neighborhood," Rubinstein said. "Everyone else left at that time - half of Williamsburg's Jews used to live in Crown Heights - but the rebbe said, 'This is where Hashem has established his blessing,' and the Chabadnikim didn't leave." The Lubavitchers of Crown Heights stopped Brooklyn's "great white flight" of the 1960s and '70s in its tracks. Throughout New York City, working class Jews and Italians, many of whom held old world views on race and ethnicity, fled for the suburbs as blacks and Latinos moved into their neighborhoods. Because this was not the case in Crown Heights, some argue that the tensions there stem from this decades-old dynamic. Still, the history of Crown Height's black-Jewish relations is mostly one of begrudging coexistence, dotted with disturbance, not the other way around. But the riots of 1991, which many Jewish residents simply call "the Pogrom," serve as a reminder of where the tensions can lead if not checked by outside forces. "This is why we have a police presence on the street," said Yossi Frankel. "In coming days and weeks it will be scaled down, and I believe things will go back to normal. Race isn't the issue here, and I don't think there's any tension. It's just early summer, and the weather is hot. These types of things happen all over the world." AP contributed to this report.