Law enforcement across the country have once again been warned by the FBI and the Department of Homeland Security about terror threats.

According to Michael Steinbach, the head of the FBI's counterterrorist division, it's individuals who fall under the radar screen those who have training but aren't known to the agency that worry him the most.Steinbach said the FBI has seen children as young as 15 recruited by ISIS and that there have been cases where parents have even encouraged their children to be involved with terror groups. He said in those cases, the FBI holds the parents responsible.We also learned last week that Hamza Ahmed, a 19-year-old Minneapolis man who is a U.S. citizen of Somali descent, was arrested and charged with making a false statement in a terrorism investigation.He is accused of lying to the FBI after authorities say he and three other young men from Minnesota took a bus to New York City and tried to board flights overseas.According to authorities, a handful of Minnesota residents have traveled to Syria, which borders Turkey, to fight with militants within the past year, and at least one Minnesotan has died while fighting for the Islamic State known as ISIS.One official acknowledged it's extremely difficult to track every American who might travel abroad to join the terrorist groups.U.S. law enforcement and intelligence agencies don't track people leaving the U.S. to vacation in Europe, so once prospective ISIS recruits get to Europe, they can easily get access to Turkey and Syria.The concern about homegrown violent extremism has also risen since last month's terror attacks in Paris.Steinbach says the term "sleeper cells" is misleading since the threat is much more complicated.He said ISIS is not only using the Internet and social media to recruit but to encourage small groups of terrorists with western passports who have a desire to attack in the U.S.Last week's execution video released by ISIS militants of a Jordanian pilot being burned alive while locked inside a cage shocked the world.The most forceful response came from Jordan's King Abdullah, who evoked Clint Eastwood's movie "Unforgiven" as a model for a measured response against ISIS butchery.Rep. Duncan Hunter Jr., a Marine Corps veteran of two tours in Iraq and one in Afghanistan, attended the private meeting Abdullah had with members of the House Armed Services Committee lawmakers last week.He said the king's anger reminded him of how Americans felt after 9/11.Our leadership in Washington and others in the civilized world need to show the same urgency to remove the ISIS cancer that appears as vicious as the Nazi ring of terror that metastasized in Europe during the 1930s, leading us into World War II.By JIM ZBICKtneditor@tnonline.com