Smoke billows from Myanmar's Rakhine state as seen from the Bangladeshi shore of Naf river (AFP)

Myanmar's army chief on Saturday blamed Rohinyga militants for an explosion outside a mosque in Rakhine state, as a rights group accused the military of starting fires in the region to prevent refugees from returning.The unrest comes days after Myanmar's civilian leader Aung San Suu Kyi declared troops had ceased "clearance operations" in the border area that have forced more than 430,000 Rohingya refugees to flee for Bangladesh in under a month.The army claims it is targeting Rohingya militants who attacked police posts on August 25. But its operation has been so sweeping and brutal that the UN says it likely amounts to "ethnic cleansing" of the Rohingya Muslim minority, a group reviled by many in the mainly Buddhist country.On Saturday Myanmar's commander-in-chief Min Aung Hlaing posted a statement on Facebook saying Rohingya militants planted a "home-made mine" that exploded in between a mosque and madrasa in northern Rakhine's Buthidaung township on Friday.The army chief accused the militants of trying to drive out around 700 hundred villagers who had remained in Mi Chaung Zay -- an argument analysts have said makes little sense for a group whose power depends on the networks it has built across Rohingya communities."As our villagers did not want to leave their homes, the terrorists blew up the bomb during the prayer time as a way of terrorizing the villagers," the army chief's statement said."It is the act of ARSA terrorist group," it added, using an acronym for the Rohingya militant group whose raids on police posts in August triggered the military backlash.No one was reported injured in the explosion.With the government blocking access to the conflict zone, it is difficult to verify the swirl of claims and counterclaims over who is driving the unrest, which has also displaced tens of thousands of Buddhists and Hindus.But rights groups say there is overwhelming evidence that the army is using its crackdown on militants to systematically purge the 1.1-million strong stateless Rohingya from its borders.On Friday Amnesty International said new videos and satellite imagery confirmed fires were still ripping through Rohingya villages, scores of which have already been burned to the ground."Not satisfied with simply forcing Rohingya from their homes, authorities seem intent on ensuring they have no homes to return to," said Tirana Hasan from Amnesty.Human Rights Watch on Saturday also echoed earlier allegations that Myanmar security forces were laying landmines along the Bangladesh border crossed by the hundreds of thousands of Rohingya seeking sanctuary."The dangers faced by thousands of Rohingya fleeing atrocities in Burma are deadly enough without adding landmines to the mix," said Meenakshi Ganguly, HRW's South Asia director.

"The Burmese military needs to stop using these banned weapons, which kill and maim without distinction."