At least 16 people are reported to have been killed by flash floods in the American State of Arkansas after floodwaters hit campsites in a mountainous national park, state governor Mike Beebe says. Two dozen people were taken to hospital and some 30 others remained unaccounted for.<br/><br/>Helicopters are taking part in the search in a remote, mountainous area in the state's south-west. The operation is focused on campsites along the Little Missouri and Caddo rivers in the Ouchita Mountains.<br/>