KINSHASA (Reuters) - Once the leafy art-deco jewel of the Belgian Congo and later the buzzing cultural heart of dictator Mobutu Sese Seko's Zaire, Kinshasa has become a playground for violent gangs sowing fear and transforming swathes of the city into "no-go" zones.
The well-organized and ruthless "kuluna", whose name derives from the Portuguese for infantry column, prey on residents with machetes, stones or iron bars under the noses of the city's corrupt and ineffectual police, activists say.
Harriet Senga watched a gang of men strike her 19-year-old neighbor with a machete and rape her in broad daylight as she collected water from a muddy stream.
When Senga tried to intervene, the men chased her through the creek. By the time the police arrived, the attackers were long gone.
"Authorities have got to start taking the gang problem seriously," the 32-year-old said. "Even if criminals are robbing and killing, police never intervene till they have left."
Youth poverty and unemployment are fuelling criminality in Congo's teeming capital, threatening government efforts to overhaul the decrepit city and attract investment.
Authorities recognize urgent action is needed to stop gang violence in the city of 10 million spiraling out of control.
According to the United Nations, Kinshasa is the fastest growing city in Africa, expected to hit 12.7 million people by 2020.
"It's now or never to tackle this," said Kinshasa police chief General Jean de Dieu Oleko. "Everyone needs to get together and reflect on how we stop it. If not, in five years we're going to have problems in our society that are unmanageable."
Turmoil in Democratic Republic of Congo, where millions died in successive civil wars, has been keenly felt in the capital.
The city was devastated by pillaging in the dying days of Mobutu's regime and swamped by an influx of people fleeing fighting. Thousands of child soldiers streamed in behind president Joseph Kabila's father when he seized power in 1997.
More than half of Kinshasa's population is under 18, most uneducated or schooled but with no prospect of work.
At least 20,000 children live on the dusty streets, and 350 more join each month, according to REEJER, an organization working with vulnerable young people.
Known as "shegues", the street children have often fled abuse and poverty at home, or been driven out by accusations of witchcraft. They weave between cars on main streets, begging for money and snatching bags if a driver leaves a window open.
"The Kinshasa we knew 20 years ago is not the same as the one we know now," said Remy Mafu, REEJER's head.
With adults neglecting their children to scrape a living, the breakdown of family means ever more young Congolese are slipping towards drugs, alcohol and criminality, he said.
"There's a revolution, a violence being born amongst the young. No one listens to them so they have to do something," Mafu said. "Little by little, if they lose hope, they join."
One TV station responds to calls from the public on kuluna attacks and rushes to film the aftermath or arrests of the alleged perpetrators. The police launch regular clean-ups, bundling anyone they can grab into the back of their trucks.
"They mistake us for criminals, thinking they've done their job and arrested a kuluna," said street kid 'DJ Blanco', an aspiring musician in a dirty soccer shirt. "They throw us in prison for five days. No-one visits and the police abuse us."
Most people in Kinshasa see the security forces as part of the problem. Police ignore gangs of youths attacking cars in broad daylight and focus on extorting bribes from motorists, many residents say.
General Oleko admits that more than 1,000 of his officers are serving time in prison but says better recruitment and training are helping to tackle indiscipline.
Joachim Ambabo, a street kid turned social worker, says the Congo's corrupt state and political elite fuels the delinquency.
"Children learn by imitation. In a country where impunity is total, how can children react?" he said.
Though the government has vowed to tackle graft, high-profile arrests are rare. Congo ranked 160 of 176 nations in Transparency International's 2012 Corruption Perception Index.
The almost total absence of social services hinders attempts to improve the situation, said Alessandra Dentice, head of governance for child protection in Congo at UNICEF.
"Lots of efforts are being made by UNICEF and other child protection agencies but it's all drops in the ocean," she said.
REEJER's Mafu says the only way to solve the problem is by involving local organizations, churches and the population.
If nothing is done, Kinshasa will become one of Africa's most hostile cities, he warned: "It will no longer be 'Kin the beautiful'. It'll be 'Kin the dangerous'."
Editing by Daniel Flynn and Sonya Hepinstall