Image source, CBSImage caption, Police officers were collecting the cash in carrier bags at the scene

A spillage from an armoured van sparked a mad scramble – and police arrests – on a US freeway on Friday morning.

Videos on social media show money raining down as people scramble to pick up dollars strewn across the road.

It happened on the Interstate 5 highway in California's San Diego county.

Police said the ensuing excitement saw drivers abandon their vehicles and block traffic. Arrests were made, with others who pocketed cash urged to hand it back.

One of the armoured vehicle's doors popped open on the road, causing bags of cash to fall out and break apart at about 09:15 (17:15 GMT) local time.

"For whatever reason, money was falling out of an armoured car," California Highway Patrol (CHP) Officer Jim Bettencourt said.

"It was free-floating bills all over the freeway."

Video captured at the scene by fitness influencer Demi Bagby shows the road at a standstill, with passers-by grabbing and playing with littered $1 and $20 bills.

"This is the most insane thing I've ever seen," she says in the clip, which then shows the usually busy highway abandoned.

Two arrests were made at the scene, local media reported.

Highway police officials said the FBI were involved and urged people who grabbed cash to come forward.

Officer Bettencourt said anyone who stopped to pick up money could "possibly be facing charges".

"If a bunch of TVs fell from a truck across the freeway, you can't just take the TVs," he said in in comments reported by the San Diego Union-Tribune newspaper.

Curtis Martin, a sergeant with the CHP, said on Friday afternoon that about a dozen people had returned money they had grabbed to police.

"People are bringing in a lot," he said, without giving a figure. "People got a lot of money."