Almost 70kg of heroin seized in northwest this year An explosion in the flow of illegal drugs from Central Asia has seen Xinjiang overtake Yunnan as the mainland's narcotics trafficking and dealing hub. By the end of last month, police in the far northwestern region had cracked 18 cases of drug smuggling from the Golden Crescent - an area that overlaps Afghanistan, Iran and Pakistan - up from four in the same period last year, Xinhua reports. The amount of heroin seized, almost 70kg, represented a jump of 12 times on the same period last year. The quantity of drugs flowing from the Golden Triangle - the opium-growing region overlapping Myanmar, Laos and Thailand - also increased, with a jump in the number of people arrested on planes and trains for trafficking drugs to Yunnan and Sichuan . Xinjiang anti-narcotics detective Zhang Shouchao said the situation was grim. He would not say more because the issue was very sensitive. 'We are not allowed to publicise figures until the leadership [of the region's police department] has reached a consensus,' he said. Ya Sen , a professor at the Xinjiang Police Officer Academy, said: 'Many investigations have not been made known to the public. The published figures represent only a fraction of the massive transportation [of drugs] from Afghanistan to China.' Surging opium production in Afghanistan was the main reason for the increase in the flow of drugs, he said. The area under opium cultivation in Afghanistan had increased 40 per cent this year so far, following a 50 per cent expansion last year, Professor Ya said. Xinjiang has a Muslim Uygur minority and borders eight countries - Russia, Kazakhstan, Tajikistan, Pakistan, Kygyzstan, Mongolia, India and Afghanistan. Before the US-led invasion of Afghanistan following the September 11 attacks, few of the drugs funnelled through Xinjiang came from that country because its radical Islamic Taleban rulers had rooted out most plantations for religious reasons. 'Many Afghans lost their savings and livelihoods in the war, and look to opium for an income ... and an increasing number of terrorists also stimulate the production and trade of opium and other drugs,' Professor Ya said. Li Yanming , a criminologist in the Xingjiang capital Urumqi , said drug dealers in the autonomous region had a national network employing more than 10,000 people long-term. The network controlled the drug supply in Yunnan, Guangdong and Beijing, Professor Li said. 'President Hu Jintao said in an internal circular that all police must be mobilised to block the Golden Crescent,' he added. But the job was complicated, Professor Li said, because the region is politically sensitive. 'Any large-scale police action could be used by [Uygur] separatists as evidence that the central government oppresses local people,' he said.