(NewsNation) — With the height of holiday shipping getting underway, FedEx recently warned all employees to be on guard for thieves targeting trucks or people swiping packages from porches.

In its security alert to its workers, including nearly 7,000 independent delivery contractors, FedEx said drivers should prioritize their safety and keep items secure.

“This Peak season is showing an increase in unlawful activity, putting increasing concern on safety and security,” the alert said, according to The Wall Street Journal. The publication notes the number of package thefts rises at the end of the year because there are more trucks and parcels on the road.

NewsNation local affiliate KSWB reported on one recent incident in California where a woman watched a robbery in front of her house. Her home security camera caught a blue car pulling up, then four to five young men getting out of the vehicle and swarming a FedEx truck.

The woman tried to stop the men by telling them about the camera, but that didn’t stop them. KWSB writes the robbery lasted 45 seconds. The driver wasn’t hurt, but the men did steal several packages.

One FedEx driver, Jazmin, says to be safe she locks her doors to “make sure there’s no access for them to be able to get into the truck and take the packages.”

In a statement to NewsNation, FedEx said it has rigorous safety and security programs but did not provide details.

Although FedEx drivers are not allowed to carry firearms, advocates have been lobbying for it.