The police said that two men, aged 42 and 45, were representing Korean Broadcasting System (KBS) News.
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Another two men, who were also from the KBS News, are also under investigation, according to the police.
"The Police would like to remind all foreigners visiting Singapore to abide by our laws. Those who break the law will be dealt with firmly, and this may include termination of visas and repatriation," said a police spokesman, as quoted by the Yahoo News Singapore.