Children like Kashif have become a major worry for social workers in Pakistan, where they are known as the "little angels of death." Pakistan has some four million drug addicts, half of whom are hooked on heroin. Some 72 percent of addicts are younger than 35, according to official figures. "It is dangerously alarming as the trend is increasing among children," said social worker, Salim Azam, who heads an organisation working to rehabilitate heroin addicts. Most of the drugs come across the border from Afghanistan, which last year became the world's top opium producer. "There are around 200,000 children heroin addicts in the country. Now children have started coming to us frequently. Kashif has come to me at leastsix times for treatment," Azam said.

But rehabilitation seems far from the mind of the frail youngster, covered in dirt. "I will get rid of this only once I am in the grave," he said. During the day he roams Karachi, begging on minibuses by reciting verses from the Koran. The money goes on heroin. "I earn 150 to 200 Rupees (three to four dollars) a day and then take the medicine," he said. "If I do not take it, then I sweat badly and my body aches. For the last six years, I have been living for this heroin."

Kashif's four young brothers are also addicts and live on the city's pavements. They learned about the drug through their father, Babu Mukhtiar, a former taxi driver and long-time addict. He sometimes uses a syringe to inject, mixing the heroin powder with lemon juice to make it soluble. Kashif has seen a lot in his short life. His mother and friends have died, his family have become beggars and visits to police stations and hospitals are regular. But every time he escapes for heroin. "Not only couldI not fulfill a promise to my dying mother but I could not protect my own brothers from addiction," he said.

Like Kashif, there are thousands of boys sleeping on pavements or in Karachi's graveyards, who crowd around roadside restaurants for leftover food. "The story starts mostly with charas (hashish) then glue sniffing and ends at heroin with death," said the social worker Azam. "The boys beg, steal or get forced into child prostitution or become the instruments of the drug pushers."

Social workers trace the history of heroin to the Afghan war which broke out in 1979, at a time when there were few addicts in the country. The Soviet invasion and years of fighting brought a Kalashnikov culture and heroin. Addicts in Pakistan spend 40 million dollars a year and consume 130 tonnes of drugs. "We are no longer a producing country but a target country," said Brigadier Mukhtiar Ahmed, a senior official of the Army-led Anti-Narcotics Force.

"It is a huge market." Now more than one million heroin addicts livein Karachi alone including 80,000 children, who often live in groups around a leader.