Second White House lockdown triggered in a week

Suspicious items thrown over the White House fence today have triggered the second security lockdown of the US President's residence this week.

President Barack Obama was not at the White House when the incident took place.

A bomb technician works with an explosives ordinance disposal robot to help recover an item thrown over the White House fence. Credit: AP Photo/Pablo Martinez Monsivais

A Secret Service spokesman said two people have been taken into custody and the suspicious items were being examined.

A car that trailed a motorcade carrying Obama's daughters Sasha and Malia on Tuesday prompted another White House security lockdown that lasted more than an hour.