The MDA identified sg.news.yahoo.com, a service run by Internet giant Yahoo, as among 10 sites that would be affected by the new requirement, based on criteria such as having 50,000 unique visitors from Singapore a month over a period of two months.
Yahoo declined to comment when contacted by Reuters.
"We are not in a position to respond until we receive the actual license conditions for review," the head of its Singapore news service, Alan Soon, said.
Of the remaining nine sites, seven are run by Singapore Press Holdings Ltd , whose publications tend to maintain a pro-government stance. The other two are operated by state-owned broadcaster Mediacorp.
Conditions for the sites that require individual licenses, which have to be reviewed annually, include a performance bond of S$50,000 and a requirement that objectionable content be removed within 24 hours when directed by the MDA.
The MDA said the new regulation did not apply to blogs, though adding: "If they take on the nature of news sites, we will take a closer look and evaluate them accordingly".
The regulation drew criticism from some Internet users who saw it as an attempt to stifle online news not affiliated with the government.
On state-owned Channel NewsAsia's Facebook page, a person named Jeremy Tan likened the development to what goes on in China or North Korea.
"You can try to shut us up. We will find a way around it," another internet user, Sushikin Ky, said on the Facebook page.
© Thomson Reuters 2013
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