Police have rounded up 36 suspected triad members and seized $180,000 worth of illicit goods including heroin and pornographic discs in a crackdown on two triad gangs in Yau Ma Tei. The 5.5-hour operation involved about 180 officers and ended at 12.30am yesterday. It targeted two triad groups, the Wo Shing Wo and Wo On Lok. 'The two triad gangs are believed to have been involved in the sale of contraband cigarettes and pirate and pornographic compact discs. They were also operating drug dens, mainly in Temple Street, Yau Ma Tei, for more than a year,' said a senior officer. 'Our investigation showed that sometimes the two gangs co-operated in running such illicit activities. Our operation was aimed at strangling their money supply.' Officers from Kowloon West regional crime unit, the Police Tactical Unit and Yau Tsim district crime squads raided up to 20 triad-controlled premises including drug dens and retail outlets for illicit goods in Yau Ma Tei. They seized $180,000 worth of goods including 261,200 non-duty paid cigarettes, 4,300 pirated or obscene video compact discs, and 20 grams of heroin. Weapons including five machetes and six iron pipes were also seized. Thirty-six men suspected to be the members of the two triad groups and three women, aged between 21 and 55, were arrested. It is the second major crackdown against triad gangs in Kowloon West after triads issued challenges to the authority of police. Police arrested 304 people and seized millions of dollars worth of illicit goods in a massive operation in Kowloon West last month.