Speaking in Oslo, Norway, Holder recommended laws and tactics leading to pre-emptive arrests of terrorists. The method, as practiced in the United States, can catch suspected terrorists before any crimes are committed. The suspects are typically charged with providing support to terrorists groups, which has led to charges the United States works to entrap Muslims.
Similar laws do not exist in many countries.
"In the face of a threat so grave, we cannot afford to be passive," Holder said.
"Rather, we need the benefit of investigative and prosecutorial tools that allow us to be pre-emptive in our approach to confronting this problem. If we wait for our nations' citizens to travel to Syria or Iraq, to become radicalized, and to return home, it may be too late to adequately protect our national security."
Authorities fear the arrival, in Syria and in other countries with dedicated militant groups, of terrorists with Western passports, who can then export terrorism back to their home countries. It is estimated that over 7,000 foreigners, including Americans, are fighting in Syria.
Notable deaths of 2014 [PHOTOS]