US auto giant Ford has halted production and shipments of the F-150 Lightning, its electric pickup truck, citing troubling signs with the vehicle’s battery pack.

The automaker on Tuesday said in a statement that the company found a potential battery issue in an F-150 Lightning during its pre-delivery quality inspections and decided to stop manufacturing and shipping vehicles while investigating the issue.

Ford added that the company is not aware of any incidences of this issue in the field, noting that the production halt began at the beginning of last week. The automaker has not clarified when it will lift up the suspension. As there was no stop-sale issued for vehicles on their way to dealers or already delivered to local shops, customers can still purchase F-150 Lightnings that are available in stock.

The F-150 Lightning, the automaker’s first major EV pickup truck, has drawn avid interest since its release in April 2022. The automaker has sold more than 15,000 units of the EV pickup. According to media reports, Ford has more than 200,000 orders in waiting for the F-150 Lightning.

The EV pickup truck runs on South Korean battery maker SK On’s NCM9 battery. An official at SK On said the company is looking into the matter with Ford, adding that there were no further details at the moment.

The NCM9 battery has been produced at SK On’s Georgia plant since last year. The NCM stands for the three main materials of the battery -- nickel, cobalt and manganese. The NCM9 battery is composed of almost 90 percent nickel.

According to SK On, the high proportion of nickel resulted in more energy storage better battery output. The EV pickup truck can travel up to 482 kilometers with a single charge based on the Environmental Protection Agency’s standards.

Shares of SK Innovation, SK On’s parent company, fell more than 7 percent Wednesday morning to as low as 154,400 won ($120) after the reports of Ford’s production halt Unlike the South Korean firm’s stock price dip, Ford’s shares decreased by only 0.92 percent to $12.97.