Lockheed Martin (NYSE:LMT) has halted production of the F-35 in Japan, and told employees in an Italian facility to work from home, due to concerns about the COVID-19 coronavirus.

Ellen Lord, the Pentagon's undersecretary for acquisition and sustainment, told reporters gathered at a defense industry conference on Wednesday that Lockheed Martin has shut down a Mitsubishi Heavy Industries Japan factory where the F-35 is assembled for at least a week, and is taking other precautions in response to the coronavirus threat.

An F-35 lands on a runway.

A F-35 fighter coming in for a landing after a test flight. Image source: Lockheed Martin.

Lockheed Martin assembles most of its F-35 Joint Strike Fighters at a facility in Ft. Worth, Texas, but the plane has a global supply chain. The company also assembles some planes to be sold to foreign partners at the Mitsubishi facility in Nagoya, Japan, and a Leonardo-owned factory in Cameri, Italy.

The company plans to deliver 140 F-35s in 2020, with most headed for the U.S. military and unaffected by the international shutdown. Lord said she has not seen any sign that the coronavirus will impact deliveries but said a Pentagon team is monitoring the virus' impact on the defense base and its suppliers.

The F-35 remains in low-rate production, but Lockheed Martin hopes to ramp up deliveries in the years to come. For that to happen, though, the company must work out some lingering issues in its supply chain that were present prior to the coronavirus, including delays delivering the plane's complex engine.

It's too soon to say whether the shutdown will be limited to just one week, or whether the Fort Worth facility will be able to avoid coronavirus-related supply chain disruptions.