Sri Lanka is prohibiting news outlets from sending mobile news alerts about military or police activity without prior approval.
Sri Lanka's defense ministry on Monday hand-delivered letters to news outlets ordering them to seek approval before sending texts about the police or military, Reuters said.
Reuters is among the news agencies that received letters.
"I have been instructed to inform you that any news related to national security, security forces, and the police should get prior approval from the [Media Center for National Security] before dissemination," the letter said, according to Reuters.
The order is effective immediately.
It comes just days after local news outlets published reports about a murder-suicide that left three Sri Lanka soldiers dead and following a report on a corrupt police officer, the news agency noted.
"This is the first step in going for wider censorship," Sunil Jayasekara, the head of Sri Lanka's Free Media Movement, told Reuters.
Agence France-Presse said the legal basis for the order wasn't clear. The order is expected to affect more than a dozen news service and Sri Lanka's estimated 18 million mobile subscribers.
The directive is the latest in a string of government efforts to censor news and information websites critical of the government as the nation works to emerge from decades of civil war.
In November, the Sri Lankan government began requiring news websites to register with its media ministry. A month earlier, the government had blocked certain cites critical of the government, AFP reported.
The news agency said 17 members of the media have been killed in Sri Lanka in the past decade.
Reporters Without Borders considers Sri Lanka a "Press Freedom Predator." Sri Lanka came in at No. 163 on Reporters Without Borders ranking of 179 countries according to freedom of the press.
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