DHAKA, Bangladesh (AP) — The United States and Britain should immediately stop supporting a Bangladeshi anti-crime force blamed for killing hundreds of suspects without trial if there is no visible effort to reform it, a rights group said Thursday.

Bangladesh on Wednesday awarded a farmer who killed more than 83,000 rats and launched a monthlong campaign nationwide to kill millions more, to protect crops and reduce the need for food imports. Mokhairul Islam, 40, won a first prize of a color...