As tens of thousands of Rohingya refugees stream across Myanmar’s border with Bangladesh, the Myanmar army’s commander-in-chief has defended clearing Rohingya villages as an essential step in rooting out a small band of militants armed with little more than spears or knives.

Myanmar has come under criticism for its actions in Rakhine State, a narrow strip of land across its national border. Since a small group of militants launched attacks against government outposts there on Aug. 25, Myanmar’s armed forces have responded with a disproportionate show of force, prompting the United Nations and the Vatican to voice their concern over the impact on the civilian population. On Saturday, Turkish President Recep Tayyip Erdogan described what is happening to Rohingya community in Myanmar, who are Muslim, as genocide.

The U.N. has said more than 58,000 refugees have made their way across the border, joining some 500,000 other Rohingya who already reside in Bangladesh, a impoverished country poorly equipped to receive them. New York-based Human Rights Watch said satellite images show many villages where Rohingya once lived have been razed to the ground; it has collected data indicating that 17 separate sites, including some where entire villages were destroyed. Myanmar’s military and members of the Arakan Rohingya Salvation Army have blamed each other for setting the fires.

“This new satellite imagery shows the total destruction of a Muslim village, and prompts serious concerns that the level of destruction…may be far worse than originally thought,” said Phil Robertson, deputy Asia director at Human Rights Watch.

Myanmar’s army, meanwhile, says 400 people have been killed in the violence, mostly Rohingya militants belonging to a new group calling itself the Arakan Rohingya Salvation Army, or ARSA.