New video shows extremist group radicalizing Aussie children

(CNN) – The Department of Homeland Security says the U.S. is ramping up its security at government buildings, following a burst of terrorist attacks last week, when a self-radicalized Muslim convert charging police officers with a hatchet in New York, and two separate lone wolf attacks left two soldiers dead in Canada.

Today in Australia, officials are outraged over the discovery of a video showing children as young as six calling for violence and chanting against the West. Australia's immigration minister called the video sickening and disturbing.

CNN terror analyst Paul Cruickshank joins CNN's "The Lead with Jake Tapper" to discuss.