Dozens of Hongkongers went to a Shenzhen detention centre yesterday to look for their children or friends who had been arrested in last week's crackdowns on drug hot spots. But they were turned away at the Longgang detention centre after being told that their friends and family members were all drug users who would be given anti-drug education over the next one to 20 days. Four hundred people aged 13 to 50, including 119 Hongkongers, were arrested early on Saturday at two entertainment parlours in Shenzhen's Futian district, near the Lok Ma Chau border crossing. Shenzhen authorities said the nightclubs' customers were asked to take drug tests by giving urine samples, and those who failed were arrested and detained. Shen Shaobao, deputy head of Shenzhen's public security bureau, said yesterday that the authority had strengthened enforcement against drug abuse, prostitution and gambling this month, and warned that more Hongkongers might be arrested for such illegal activities. Police had said such activities had increased in the first six months of the year amid the economic crisis, he said. Police from nearby districts had been deployed to conduct the operations, apparently to avoid any tip-offs before the raids. Hundreds of Longgang district police officers sealed off the two nightclubs. A Hong Kong man who refused to give his name said more than 10 of his friends had been arrested on Saturday at the St Paul Disco, and they might have to remain in custody until Friday. 'The police handled the cases very strictly this time,' he said. 'My friend could not get away from detention though I tried to pay the detention house.' A man in his mid-40s, who was released yesterday after paying a 500 yuan (HK$560) fine, said: 'We were all locked up in the detention house, 30 people per cell. 'They separated Hongkongers from mainlanders, and everyone had to wear the same orange uniform. We were not forced to do labour, but we had to listen to anti-drug and anti-prostitution programmes.' The raids came two weeks after a pledge by Shenzhen's acting mayor, Wang Rong, to step up co-operation with Hong Kong to tackle drug abuse. A spokeswoman for Hong Kong's Security Bureau said it had reached an agreement with Shenzhen authorities to repatriate Hong Kong young people after the detention period ends, but details were pending further discussions. Shenzhen authorities have agreed to share information on young drug abusers with Hong Kong police, who will contact their parents. The opening of the border 24 hours a day in 2003 spurred an increase in cross-border trips by young Hongkongers lured by lower prices for illegal drugs in Shenzhen. 'Most of our customers are from Hong Kong. They come late, stay here until early morning and go back to work the next day,' a Shenzhen nightclub disc jockey said.