As part of our layered approach, we have expedited the deployment of new Advanced Imaging Technology (AIT) units to help detect concealed metallic and non-metallic threats on passengers. These machines are now in use at airports nationwide, and the vast majority of travelers say they prefer this technology to alternative screening measures.

It's always been government's role to protect the security of the nation. And cyber-attacks is a security issue, from our perspective. And it's a security issue of particular concern with respect to the nation's core critical infrastructure, the infrastructure everyone relies on, the energy sector, the telecommunications sector, the banking sector.

We are on the lookout for criminal and terrorist activity but we do not nor will we ever monitor ideology or political beliefs. We take seriously our responsibility to protect civil rights and liberties of the American people, including subjecting our activities to rigorous oversight from numerous internal and external sources.

Let me be very clear: We monitor the risks of violent extremism taking root here in the United States. We don't have the luxury of focusing our efforts on one group; we must protect the country from terrorism whether foreign or homegrown, and regardless of the ideology that motivates its violence.

It would be unwise to say the least, irresponsible of us at the TSA, at the Homeland Security Department not to evolve our technology to match the changing threat environment that we inhabit.

Nonetheless, to the extent that terrorists have come into our country or suspected or known terrorists have entered our country across a border, it's been across the Canadian border. There are real issues there.

There are a number of countries that we see cyber-attacks emanating from. And, again, they can be just individuals who are located in the country. But three that I think are of special concern would be Iran, would be Russia, and China.