Top US officials are warning that militant plots to attack the United States are growing increasingly harder to detect. Speaking before a Senate hearing, Homeland Security Secretary Janet Napolitano said a large number of small-scale plots has made disruption more challenging.

Homeland Security Secretary Janet Napolitano: “We are also seeing more diversity in terms of tactics. Recent events in intelligence show a trend toward, as you mentioned, Senator Collins, smaller, faster-developing plots, rather than larger, longer-term plots like 9/11. These plots may include the use of IEDs or teams who use small arms and explosives, both forms of attack that have been used abroad. The results of these changing tactics are fewer opportunities to detect and disrupt plots.”