Letters sent to the South Korean and Pakistani embassies in Thailand threatening America’s Asian allies sparked fresh security fears on Thursday as Washington told the region to be on alert for attacks on its crowded sea lanes. Speaking in Singapore, a top State Department official said U.S. authorities had good reason to believe terror groups would target critical shipping routes such as the Malacca and Singapore straits. Seoul ordered an immediate extension of already heightened security measures at ports and airports in response to a letter signed by a hitherto unknown group calling itself the ‘Yellow-Red Overseas Organization’. Full Story