Hundreds of Rohingya Muslims are fleeing a military crackdown in western Myanmar to Bangladesh, trying to escape an upsurge of violence that has brought the total number of dead confirmed by the army to more than 130. Some of the Rohingya were gunned down as they tried to cross the Naaf river that separates Myanmar and Bangladesh, while others were pushed away by Bangladeshi border guards and may be stranded at sea, Bangladeshi authorities and residents said. The bloodshed is the most serious since hundreds were killed in communal clashes in the western Myanmar state of Rakhine in 2012. It has exposed the lack of oversight of the military by the seven-month-old administration of Nobel Peace Prize winner Aung San Suu Kyi. Soldiers have poured into the area along Myanmar's frontier with Bangladesh, responding to coordinated attacks on three border posts on Oct. 9 that killed nine police officers. They have locked down the district, where the vast majority of residents are Rohingya, shutting out aid workers and independent observers, and conducted sweeps of villages, the authorities, diplomats and aid workers have said. The army has intensified its operation in the last seven days and has used choppers to reinforce, with dozens reported killed. Aid workers, camp residents and authorities in Bangladesh estimated at least 500 Rohingya had fled Myanmar to Bangladesh since the October attacks. The refugees are now staying in four Rohingya camps on the Bangladeshi side of the border, they say. But on Tuesday, Bangladeshi border guards pushed back a large group of Rohingya trying to cross. — Reuters