The Islamic State has "become better at what they do" — as evidenced by the Berlin attack that killed 12 people and injured 50 others, Rep. Darrell Issa, R-Calif., said Tuesday.
"Their network may be diminished in some regions, but it has become a more capable worldwide organization," Issa told CNN's Brianna Keilar. "Particularly one that does comparatively minor but easy to set up, easy to execute assassinations.
"Whether it is one individual such as in Turkey or a truck such as in Berlin," he continued. "These so-called, sometimes lone wolves are very good at setting up terror on a regular basis."
Issa said he expected President-elect Donald Trump to battle terrorism more fiercely because he "has vowed to take fight to ISIS around the world, which makes the domestic job inherently easier."
Trump also nominated retired Marine Corps Gen. James Mattis as defense secretary because "he thinks there needs to be an organizational reform of the Department of Homeland Security," he said.
"I couldn't agree with him more.
"As much as there are good men and women at for example, TSA, it is a large organization — often found to be poorly organized and certainly not having the kind of discipline that allows them to predictably catch what should be caught and get people through in an expeditious basis.
"The real failure of the Obama administration was the failure of the State Department to take serious the growth of terrorism," Issa added. "It is a failure of our military to be deployed in an efficient fashion."