Most of the detainees were Chinese men and women, an official involved in the raid told AFP on condition of anonymity.

The official said the majority would be charged with violating the conditions of their tourist visas and working illegally.

"We are still in the process of compiling a list of the suspects," the official said, adding that computers and mobile phones used by the suspects had also been seized.

Tuesday's arrests in the northcentral district of Anuradhapura were the biggest since October 2024 when authorities detained 230 Chinese nationals operating cybercrime centres in several parts of the island, immigration officials in the capital said.

At the time, the Chinese embassy said Beijing's crackdown on cybercriminals may have pushed some abroad.

In 2024, Sri Lankan police arrested 200 suspects, mainly Indian nationals, who were also accused of operating online financial scams.