Since then the boundary area has often been unstable owing to armed conflicts such as the Chittagong Hill Tracts conflict (1977-1997) in south-east Bangladesh and the Rohingya conflict in Myanmar's Rakhine state. The latter has been ongoing for decades, yet has reached a particular intensity since 2016. The latest round of fighting has resulted in Rohingya refugees crossing the border from Myanmar into Bangladesh. Bangladesh and Myanmar have agreed to close their borders during sudden influxes of Rohingya refugees. On Myanmar's side of the border in Maungdaw District, 80 percent of the population is Rohingya. In 2014 members of the Myanmar Border Police opened fire on a Border Guards Bangladesh (BGB) patrol, killing one. In 2015 an armed clash occurred on the border between the Rohingya Arakan Army and the BGB. There have also been a number of incidents down the years involving fishermen on the Naf river allegedly illegally crossing the boundary.