680 Chinese nationals, suspected of operating an extensive online fraud operation cheating people in their homeland, are in custody following the biggest single operation by the Immigration Department.

Wednesday's raid in Cyberjaya was the end result of a month's worth of surveillance by the department, which acted on complaints made by the public.

In a press conference on Thursday, Immigration Department director-general Datuk Khairul Dzaimee Daud said the police and department would work together to round up another 100 suspects who managed to escape.