F-35 jets are made at a Lockheed Martin factory in Ft. Worth, Texas but allies assemble jets for themselves at two final assembly and check out facilities (FACO) in Japan and Italy.

"In Japan, I believe they shut down the FACO for a week," Ellen Lord, the Pentagon's top weapons buyer, told reporters on the sidelines of a defense conference in Washington.

Still, deliveries were not impacted, Lord said.

"In Japan, to comply with Japanese Coronavirus directives, Mitsubishi Heavy Industries is temporarily closing the Japanese FACO for one week; of note, only Japanese aircraft are produced at this FACO," Air Force Lieutenant Colonel Mike Andrews, a Pentagon spokesman said in a statement.

At the F-35 FACO plant in Italy, "Lockheed has directed their employees to work from home," Lord said.

Pratt and Whitney, which makes the engines for the jets, has told its team in Italy to telework, but "there have been no impacts to the production line," Andrews said in the statement.

A Lockheed Martin representative said the company was "working with our customers and partners to mitigate any impacts to F-35 international FACO operations in Italy and Japan."

By Mike Stone