Top officials have long been warning about the threat posed by ISIS . The group has claimed responsibility for a number of attacks in recent years and is believed to be behind several plots against Western targets. The terror groups , Flynn wrote , had `` exploited the permissive security environment to increase its operations and presence in many locations and also has expanded into Syria and Lebanon to inflame tensions throughout the region . '' It was also hard to predict Iraq 's defense capabilities , the White House says .
Top officials have long been warning about the threat posed by ISIS . The group has claimed responsibility for a number of attacks in recent years and is believed to be behind several plots against Western targets. It was also hard to predict Iraq 's defense capabilities , the White House says .