Thailand has threatened to ban foreign-owned mobile phone operators which government leaders suspect could be bugging their mobile phone conversations, regional media have reported.
Government ministers have promised an investigation, and threatened to revoke the licences of telecoms operators caught eavesdropping.
"The armed forces are currently experiencing a problem. We pick up the phone and the line runs to Singapore. We can talk about confidential official matters, but it goes to Singapore," Thai junta leader Sonthi Boonyaratkalin alleged in a speech earlier this month, according to Singapore's Straits Times.
Thailand's largest mobile phone operator, Advance Info Service (AIS), was taken over by a company close to Singapore's government last year.
Some Thai leaders have since switched to other mobile phone firms or even to using walkie-talkies, local media reports say.
Although AIS is controlled by an ostensibly private Singaporean company, Singapore's government has responded to the Thai allegations.
"It does not make business or technical sense to route domestic calls via another country. Doing so will incur additional and unnecessary network resources and degrade the quality of service," said a Singapore Foreign Ministry spokesman, according to Singapore's Today newspaper.
"Singapore maintains a strict and professional operating environment to safeguard the integrity of all communications which terminate in or transit through Singapore."
Exacerbating the dispute has been Singapore's cordial treatment of deposed Thai prime minister Thaksin Shinawatra, who visited Singapore this month and met unofficially with the deputy prime minister.
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