Police have arrested hundreds of people and seized illicit goods - ranging from ketamine and cough syrup to dutiable cigarettes and illegal fuel - in a massive operation against triads in Hong Kong over the past four days. The crackdown, codenamed Sunrise, is a joint operation by police from Hong Kong, Macau and Guangdong, and will continue for another week. It is aimed at cutting off the money supply of the triads, sources say. In Hong Kong, the Organised Crime and Triad Bureau co-ordinated raids with assistance from officers from various forces. The operation began on Wednesday. The crackdown is reportedly an annual event, targeting organised crime and triad activities before the National Day on October 1. 'The operation mainly targets the revenue sources of various triad societies, as well as their cross-border activities,' a police source said. 'Their income is generated from their illegal activities, which include vice, gambling, drug trafficking and the sale of contraband cigarettes, pirated compact discs and illicit oil.' Police from various districts had been sent to at least 200 premises including pubs, karaoke lounges, gambling and drug dens, brothels and guesthouses. Hundreds of people had been arrested in the raids in Hong Kong, including suspected triad members, mainland prostitutes, gamblers and drug traffickers, another police source said. Officers arrested 60 mainland prostitutes during an anti-vice crackdown in Yuen Long on Friday afternoon. Police said 42 of the 60 women were caught in 10 brothels, while 12 others were picked up on the streets. Twenty of the 60 were reportedly individual travellers and another five were holders of multiple-entry permits with business visas. They were handed over to immigration officers for further investigation. Yesterday, Inspector Fung Ngar-jing, of Yuen Long police station, confirmed the anti-vice sweep was part of the Sunrise anti-triad operation. 'We suspect that triad gangs arranged for the mainland women to work in Yuen Long, and offered them accommodation,' she said. Two triad societies - 14K and Wo Shing Wo - are understood to be active in Yuen Long. Meanwhile, at 2am yesterday, Narcotics Bureau officers arrested four men and seized 1kg of the designer drug Ice in Cheung Sha Wan.