(CNN) A top United Nations official has warned of "serious implications for human rights" in parts of Myanmar after the government shut down mobile data networks.

"The directive, which makes references to the Myanmar's Telecommunication Law, does not specify when the shutdown will end. As basis for its request," Telenor said in a statement, adding that officials "referenced disturbances of peace and use of internet services to coordinate illegal activities."

The Myanmar military, also known as the Tatmadaw, has been conducting a major security operation and crackdown in the western province of Rakhine since August 2017, when alleged Rohingya militants attacked police posts.

More than 720,000 Rohingya are estimated to have been forced to flee into Bangladesh as a result of the ensuing violence, which US lawmakers and international human rights bodies have said amounts to ethnic cleansing and even genocide

The unrest caused by the anti-Rohingya crackdown and exodus has been exacerbated by conflict between the Tatmadaw and the Arakan Army, a Buddhist insurgent group, which has been fighting with the government since last year . More than 35,000 civilians have been displaced by the conflict, according to the United Nations, with violence spilling over into neighboring Chin state.

U Myo Swe, an official with the Ministry of Transport and Communications, told the Irrawaddy , a Myanmar news site, that this month's internet shutdown was "for the sake of security and the public interest."

"All of us know the situation in Rakhine. People are in trouble, and many people have been displaced. The internet is one of the contributors to this. So, it has been temporarily suspended. It will be resumed when stability is restored," U Myo Swe said.

Yanghee Lee, the UN Special Rapporteur on the situation of human rights in Myanmar, said the internet shutdown could have the precise opposite effect, however.

"As there is no media access and serious restrictions on humanitarian organisations in the conflict-affected area, the entire region is in a blackout," she said in a statement. "I fear for all civilians there, cut off and without the necessary means to communicate with people inside and outside the area."

Lee said the UN had been informed the Tatmadaw was conducting a "clearance operation" which "we all know by now can be a cover for committing gross human rights violations against the civilian population."

Shawn Crispin, the senior Southeast Asia representative for the Committee to Protect Journalists (CPJ), said the shutdown "deliberately impedes journalists' ability to send, receive, and publish reports from Rakhine and Chin states."

"Authorities should lift their censorship order and allow reporters to report freely on the region's armed conflict," Crispin added in a statement

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Online blackout

Internet shutdowns have become increasingly common across the world in recent years , especially Asia, often in the wake of protests or other anti-government activity. Other governments have moved to legislate greater internet controls in the wake of terrorist attacks or violence such as that in Christchurch, New Zealand earlier this year.

Yet there is little evidence to support justifications for the bans -- particularly nationwide ones -- which experts say do not hinder terrorists and may increase the amount of fake news and rumors being spread because they can't easily be rebutted.

"Nationwide internet restrictions accelerate the spread of disinformation during a crisis because sources of authentic information are left offline," Netblocks, a group which tracks internet shutdowns worldwide, said in a statement . "This allows third parties to exploit the situation for political gain and profit."

Adrian Shahbaz, a researcher at Washington-based Freedom House, said that "shutdowns are a blunt instrument for interrupting the spread of disinformation online. Citizens are denied access to communication tools at a time when they need them the most to dispel rumors, check in with family, or avoid dangerous areas."

"It's alarming to see the practice of blocking communication apps become normalized around the world as a policy tool," he said, adding that at least 21 countries blocked social media in 2017 and 2018. The world's largest democracy, India, is the worst offender, with almost 60 shutdowns in 2018 alone, according to monitor Access Now