WASHINGTON — A Homeland Security official said this morning the government will now require airlines to check updated no-fly lists within two hours of being notified of changes to the list.

The alleged Times Square bomber, Faisal Shahzad, was able to board an airplane despite being on the list, because Emirates airlines did not look at an updated list that included his name.

The official says that until now, airlines have been required to check for updated lists every 24 hours. The official spoke on condition of anonymity because he was not authorized to speak publicly on this change.

When updates are made to the no-fly list, notifications to airlines instruct them to check the updated list. The official says airlines could be fined if they don't comply.