Members of a triad gang known as snakeheads were among 36 people arrested in Macau for allegedly being involved in a human smuggling syndicate.

On Saturday, law enforcement officers in Macau carried out raids in various parts in the city, including a construction site on Rua Formosa, Rua do Canal Novo, Rua de Brás da Rosa, Rua Dois do Bairro da Areia Preta and Rua de Francisco Xavier Pereira and arrested 18 people for alleged human smuggling and overstaying visas, the Macao Daily News reported.

Four Vietnamese men aged between 21 and 41 and believed to be snakeheads, or members of a triad gang, a 37-year-old Vietnamese domestic worker who provided accommodation to illegal migrants and a 60-year-old local man who employed them at a construction site were arrested. The rest, aged between 25 to 54 were illegal migrants.

Guangdong province police and customs officials also arrested 18 people in Zhuhai – seven believed to be snakeheads and 11 illegal immigrants from Vietnam. Police believe the syndicate had been operating for at least two years.

Police said Vietnamese first illegally entered Guangxi province in China and were then transported to Guangdong province. After staying in Zhuhai for a few days, snakeheads led them to swim across the waters from Zhuhai to Macau with the help of life-jackets and ropes, adding that each one had to pay about 4,000 to 5,500 Chinese yuan (US$509 to $701) to the syndicate.

The illegal entrants then stayed in the city and worked illegally.

Both Macau and Guangdong province officials said they will further investigate the syndicate and have not ruled out the possibility of more arrests.