Homeland Security Secretary John Kelly cited border security, defeating transnational crime rings and domestic terrorist attacks as the three biggest problems facing his department, during an interview on NBC’s “Meet the Press” on Sunday.

“I think really the biggest challenge is day in and day out and it’s a 24/7 thing,” Kelly told host Chuck Todd. “Protecting, securing the southern border certainly is very important, but just protecting your nation from transnational criminal organizations that are largely resident in the United States, but have tentacles outside the country. And then the terrorist threat, a potential terrorist threat, whether it’s home-grown or from overseas.”