LOS ANGELES (AP) — The Transportation Security Administration says security checkpoint operations will stop at hundreds of U.S. airports at 12:20 p.m. Eastern Standard Time today.

That's when one week ago, TSA agent Gerardo Hernandez was shot and killed by a gunman at Los Angeles International Airport.

Two other TSA agents and a bystander were wounded.

Airports across the country will hold a moment of silence.