White House on Lockdown, Lifted Shortly After

April 7, 2015 Updated: April 7, 2015

The White House was placed on a security lockdown on Tuesday afternoon, according to reports.

Veteran CBS News White House correspondent Mark Knoller reported: “WH now in security lockdown.”

He later wrote: “Secret Service says WH lockdown unrelated to power outage. It was an unattended package in Lafayette Park. All clear just given.”

There was a power outage that hit much of Washington D.C. and Maryland on Tuesday.

It was reported that an explosion at a power plant caused the outage.

Many of the outages were brief, but others were longer and forced evacuations.

At the White House, backup generators kicked on when the power went out, so the interruption lasted only a few seconds. The complex quickly went back onto regular power. Electricity in the press briefing room dipped around lunchtime, briefly darkening cubicles and blackening TV screens.

Power also went out at the State Department during the daily press briefing, forcing spokeswoman Marie Harf to finish her comments to reporters in the dark.

Power in the U.S. Capitol Building twice shut down briefly, then came back on by way of a generator.

The Associated Press contributed to this report.