Story highlights

U.S. Embassy staff alerted Norwegian police to the suspicious object

Police say a fake bomb had been attached to a vehicle as part of a U.S. terror drill

The area around the U.S. Embassy was evacuated after the alert

CNN  — 

A fake bomb attached to a vehicle as part of a terrorism drill by the U.S. Embassy in Oslo triggered a security alert at the embassy Tuesday, a Norwegian police spokeswoman said.

The U.S. Embassy had a rehearsal for a terrorism incident last week, spokeswoman Siv Alsen of Norway’s Police Security Service said.

They “used fake bombs, and one of those bombs was not removed” from the vehicle it was attached to, Alsen said.

U.S. Embassy staff had alerted police to the presence of a “suspicious object” under a car parked near the Embassy building Tuesday morning.

The area was evacuated and a cordon put in place 500 meters around the U.S. Embassy, police spokesman Bjorn Jorgensen said.

The object was then discovered to be a mock device.

A bomb attack by Anders Behring Breivik targeting Norwegian government workers rocked Oslo just over a year ago. He admitted responsibility for the bombing, in which eight people died and several others were injured. He then went on a shooting spree on Utoya Island, killing 69 more.

CNN’s Stephanie Halasz contributed to this report.