Myanmar's military has killed about 30 Rohingya Muslims in Rakhine state on Sunday, state media reported on Monday, marking the largest escalation of the conflict since fighting erupted in the northwest a month ago.
The violence is the most serious to hit Rakhine since 2012, when communal clashes between Rakhine Buddhists and Rohingya Muslims killed hundreds and forced thousands to flee.
Soldiers have poured into the Maungdaw area along Myanmar's frontier with Bangladesh in the north of Rakhine, responding to coordinated attacks on three border posts on October 9 in which nine police officers were killed.
Security forces have locked down the area, shutting out aid workers and independent observers before conducting sweeps of the villages.
Skirmishes took place throughout the weekend, with state media reporting casualties sustained on both Saturday and Sunday.
New satellite images released by Human Rights Watch on Sunday showed widespread destruction of Rohingya villages, including some 430 homes that have been burnt down.
Residents and human rights advocates have accused security forces of summary executions, rapes and setting fire to homes in the recent violence.
However, the government and the army reject the accusations, saying they were conducting "clearance operations" in the villages in accordance with the rule of law.
Since October 9, more than 60 Rohingya Muslims and 17 Myanmar troops have been killed.