Speaking to the Center for New American Security, the DHS chief said if airline carriers refused to follow any of the new security measures they could be banned from operating direct flights to the US.
"The threat has not diminished. In fact, I am concerned that we are seeing renewed interest on the part of terrorist groups to go after the aviation sector," he said Wednesday.
Kelly's announcement comes as a "watered down" version of the Trump administration's long delayed travel ban will come into effect at 8 p.m. ET Thursday.
Unless they are able to demonstrate a "close relationship" with a US person or entity, people from Libya, Syria, Iran, Somalia, Yemen and Sudan are banned for 90 days.
Kelly said the other new measures "will be both seen and unseen, and they will be phased in over time. His agency refused to detail all of the new requirements for security reasons.
Among those measures announced by the DHS chief are greater scrutiny of passengers entering the US, enhanced screening of electronic devices, and better deployment of canines that detect explosives -- requirements which many in the airline industry expected.
Kelly also said that his department "will encourage more airports to become pre-clearance locations."
He cited the new measures as a first step in raising "the global baseline of aviation security," making "it harder for terrorists to succeed." The agency says the move is a way to address the threat that intelligence suggests is looming without having to do an all-out laptop ban
Agency officials said the measures are a directive for airlines to follow since DHS does not have jurisdiction over foreign airports. They do, however, have jurisdiction over air carriers with direct flights to the US.
Earlier this month, Kelly told CNN
that the 10 airports that were first hit with the laptop ban would be given an opportunity to get off the list if they took certain steps. He did not specify what those steps were.
The DHS did not give a solid date for when the new measures would go into effect, saying only that it would be up to the airlines to determine how quickly they can get up to speed.