More than 250 Chinese accused of involvement in international telecommunication fraud rings were returned to China on Tuesday to stand trial, the Ministry of Public Security said.

Authorities in Indonesia and Cambodia transferred 254 suspects, all from the mainland, to police. They arrived on chartered flights at airports in Beijing, Shanghai, Hangzhou and Guangzhou, the ministry said.

The telecom fraud occurred in more than 20 provinces and regions across the country, and included 4,000 major crimes in HongKong, the ministry said.

The volume of cross-border telecom fraud has been rising sharply in recent years, and the suspects worked abroad to "use modern technical means and quick online banking transfers to swindle the public", according to a ministry statement.

The ministry said most of the suspects were unemployed, young and not well-educated people from the mainland who were tricked into working for the criminal rings in southeast Asian countries under the guise of introducing them to well-paid jobs.

A four-month campaign to quash the criminal telecom fraud gangs began in August. In October, the ministry sent special teams to Indonesia and Cambodia that worked closely with police in Taiwan and Hong Kong to identify and locate suspects and collect evidence.

On Oct 19, mainland police, assisted by officers from Taiwan and HongKong, worked closely with Indonesian police to conduct raids in which 138 suspects from Taiwan and 86 from the mainland were detained.

Meanwhile, Guangdong police arrested 39 suspects who had returned to the province from Indonesia and the Philippines, and they uncovered more than 3,000 international telecom fraud crimes, including many in Hong Kong, the ministry said.

On Oct 31, mainland police worked with Cambodian police and immigration officers to bust three telecom fraud enterprises and detain 168 suspects in Cambodia. They also seized computers, cellphones and banking cards, the ministry said.

The ministry said it will review evidence collected in the cases in an effort to prevent any further such crimes. Enhanced cooperation on intelligence sharing, case investigation and apprehension of suspects is also planned with counterparts in Taiwan and Hong Kong as well as in other countries, it said.

zhangyan1@chinadaily.com.cn