Authorities believe they have busted a large gang involved in call scams and online gambling.

Police detained 23 Chinese nationals during a series of raids on rented apartments and houses in the Sadao district of Songkhla overnight, and confiscated a large number of computers, ATM cards and cell phones.

The raids were made by teams of police, soldiers and local administrators.

An assistant national police chief flew to Songkhla from Bangkok to join in the interrogation of the suspects.

The swoop followed local complaints about large numbers of Chinese people working, using computers around the clock, in rented houses and apartments near the Malaysian border.

Authorities raided 11 rented apartments and houses late Wednesday night and detained 19 Chinese men and four Chinese women.

They also seized 19 desktop computers, 23 notebook computers, 47 mobile phones, a banknote-counter, 113 ATM cards, two safes and cash in mixed currencies - 50,000 baht, 30,000 yuan and 300 ringgit. Police were hoping to examine data stored in the password-guarded computers.

Local police said investigators had monitored the gang's activities for about five months. The Chinese people refused to answer interrogators' questions and were detained at the immigration office of Sadao district.