There aren't a lot of details on the enhanced security measures just yet, but they include more thorough passenger and electronic device screening, increased security protocols in passenger areas and around aircraft, greater use of explosive-detecting canines and more preclearance locations. Reuters reports that airlines flying into the US from any of the 280 originating airports worldwide have 21 days to implement more thorough explosive screening measures. They'll have 120 days to phase in the other security enhancements.

Those airlines that don't comply could face a ban on electronic devices -- like the one implemented in March for a number of Middle East airlines -- or a suspension of their US-bound flights.

"While the actions we are announcing today will improve the security of US-bound flights, I am hopeful other nations will follow suit. Unless we all raise our security standards, terrorists—who see commercial aviation as the greatest takedown—will find and attack the weakest link," said Kelly.