At least 13 people have been killed in extensive flooding that also stranded nearly 4.5 million people in eastern Bangladesh, the government said on Friday, as army troops try to reach areas cut off by the water. Days of heavy rains and a surge of water flowing down from upstream hilly areas caused local rivers to burst their banks, leading to widespread devastation. Kamrul Hasan, a senior official at the Ministry of Disaster Management and Relief, said 12 out of a total of 64 administrative districts are affected by the flooding that left 13 people dead as of Friday. He said nearly 4.5 millio…