Harare - For opponents of Zimbabwe's veteran President Robert Mugabe, internet data charges have become a key battlefront in their campaign against a regime that often cracks down violently on dissent.Last week, the state's telecommunications authority approved a sharp increase in mobile data prices - triggering a furious public response that forced a surprise U turn.Under the proposed tariffs, the minimum cost for internet data would have tripled from two US cents per three megabytes to two cents per megabyte."The proposals highlighted government's determination to stifle the free flow of information," Promise Mkwananzi, a leading activist and spokesperson of the Tajamuka protest movement, told AFP."Mobile tariff increases show intolerance on the part of government in its attempt to slow down mobilisation of people on social media."Late last year, Techzim, an information technology website, reported that Zimbabwe had the third highest pre-paid mobile data in Africa.Facebook, Twitter and WhatsApp activity was a driving force behind a new protest movement last year that led to work boycotts and street demonstrations that shook the regime of 92-year-old Mugabe.Evan Mawarire, a little-known pastor, emerged as the movement's leader after he posted an unscripted Facebook video denouncing the government's failures.The clip of Mawarire wearing the Zimbabwean national flag around his neck spread rapidly, with the hashtag, "ThisFlag", becoming a full-fledged anti-Mugabe slogan.But in the weeks that followed, street protests were crushed by security forces, many political opponents were beaten up or kidnapped by suspected state agents, and Mawarire fled to safety abroad. 'Suppress public dialogue' Harare resident Oswell Miti told AFP in downtown Harare that the proposed price hike was a ploy by the authorities "to deter people from going on the internet and to minimise the number of users."Lawyer and activist Fadzayi Mahere called the increase "unjustified" and said it was "a violation of basic rights."With Mugabe due to stand for re-election next year, Crisis in Zimbabwe Coalition (CZC) - an umbrella action group - said expensive internet and phone data were part of a government plan to suppress public dialogue that often focuses on the president's age and his likely successors."Social media became communication for impoverished Zimbabweans and provided a platform for discussion of issues such as democracy," CZC spokesperson Dumisani Nkomo said.Last year, authorities shut down telecommunications on at least one day when a major anti-Mugabe protest was planned, making it impossible for people to organise via WhatsApp or email.The Postal and Telecommunications Regulatory Authority of Zimbabwe (Potraz) has also warned it would arrest people who send or pass on communication deemed to be offensive or detrimental to state security.Zimbabwe has over 12 million mobile phone lines in use shared between three mobile companies: Econet, which is the largest, NetOne, and Telecel.With unemployment over 90% and the economy in tatters, Zimbabwe could be set for more waves of dissent as ailing Mugabe struggles to impose control.For now, the government has backed off the sensitive issue of data costs, reversing its stance and instead accusing telecoms companies of greed.Information and communication technology minister Supa Mandiwanzira last week described the margin by which the prices would have gone up as "shockingly high" and that they reflected "insensitivity" to Zimbabweans.