Authorities were forced to shut down the Sumas border crossing Thursday after agents discovered a grenade in a vehicle that was headed into Canada.

The grenade was eventually determined to be inert, but not before causing an unnecessary kerfuffle that lasted several hours and required the efforts of an Explosives Disposal Team.

The Canadian Border Services Agency said agents found the dangerous-looking item in a vehicle that approached the Abbotsford, B.C. crossing at around 2:45 p.m.

Three people were taken into custody as the CBSA closed the border and called the Abbotsford Police Department for assistance.

Staff Sgt. Rick Stewart of the APD sent a tweet around 6:30 p.m. revealing the people responsible had made no apparent effort to conceal the grenade.

“Cutting through BC? Don’t have grenade in plain view,” Stewart said. “No entry for u.”

Agents spent hours searching a U-Haul and another vehicle, pulling out several items you would expect to see from people moving homes, including a bike and a cat tree.

There were also a number of military-style bags labelled “zombies.”

It's unclear whether the people who were taken into custody will face any charges.

Single northbound and southbound lanes were opened back up to traffic within about a half hour of the initial border closure.