The US Postal Service has a message for hoverboard makers: Keep those things off our airplanes.
USPS is limiting shipping options for self-balancing scooters due to safety concerns after reports that some hoverboards have caught fire.
"Effective immediately and until further notice, the Postal Service will ship the hoverboards only using Standard Post/Parcel Select, which travels on ground transportation, due to potential safety hazards pertaining to lithium batteries," said a USPS spokeswoman in an emailed statement Wednesday.
USPS said it made this decision "out of an abundance of caution" after major retailers stopped selling some brands of hoverboards and several airlines banned them from planes. Items shipped via Standard Post are usually delivered in two to eight business days, according to the USPS website.
The Postal Service's decision was previously reported by the San Jose Mercury News.
This is just the latest knock against hoverboards, which despite their name do not really hover. The boards, most of which are powered by lithium ion batteries, feature two wheels with a platform between them. The reported fires have been linked to overheating of the boards' batteries.
Most major US airlines, including American, Delta, United and Southwest, banned the boards from carry-on or checked baggage due to safety concerns about their batteries. Online retailer Overstock said last week that it will no longer sell them, and Amazon has also removed several brands of hoverboards from its site.
Hoverboards made by Swagway vanished from Amazon last week, a development that seemed to be related to a safety notice Swagway says it received Friday from the Seattle-based Internet retailer. As of Wednesday, Swagway boards are once again for sale on Amazon.
USPS also said hoverboards may not be sent in international mail shipments and are prohibited in shipments to and from overseas military and diplomatic destinations.
Lithium batteries are allowed in the mail, as long as they meet USPS rules and regulations.
CNET's Sean Hollister contributed to this report.