UPDATE: Security incident at White House

Posted at 1:42 PM, May 30, 2016
and last updated 2016-05-30 14:09:22-04
Police moved into action at the White House Monday on Memorial Day after a suspicious package was thrown over the fence.

Bystanders broke out in a shower of tweets about a lockdown at the White House Monday afternoon. And though no major news agency had confirmed a lockdown specifically, at about 1:25 p.m., a Reuters correspondent tweeted that he and other reporters were not able to leave the White House because of an incident.

Twitter users were the first to get the news out with a blast of eye-witness accounts about emergency vehicles near the White House, which is located at Pennsylvania Avenue, NW and 16th Street, NW.

One user posted video of a fire truck and several Hazmat trucks lined up on 17th Street near the White House.

This is a developing story.