Gunfire and explosions crackle in the hills. Plumes of smoke from burning villages streak the monsoon-grey sky. Refugees fleeing for their lives are pouring into Bangladesh over the Myanmar border as the conflict between Myanmar security forces and Rohingya militias escalates and risks spiralling into a humanitarian disaster.

The refugees say their villages are being raided and burned. They tell stories of the indiscriminate killing of civilians at the hands of security forces and Buddhist nationalists. Since 25 August, more than 18,500 Rohingya, a largely Muslim ethnic group, have fled into Bangladesh from Rakhine state. However, UN sources say they believe the true figure is closer to 28,000. And Bangladeshi aid workers claimed on Saturday that 70,000 – almost 10% of the Rohingya population – had crossed in less than 24 hours.