On Sept. 23, 2016, senior Japanese and U.S. government officials joined Lockheed Martin to celebrate the roll out of the first Japan Air Self Defense Force F-35A Lightning II.

WASHINGTON — Work at the F-35 fighter-jet factory in Japan has paused for a week due to concerns over the coronavirus outbreak, a U.S. defense official said on Wednesday.

The F-35 fighter, the Pentagon's most expensive weapons program, is manufactured by Lockheed Martin in Ft. Worth, Texas. International program partners assembly their versions of the aircraft at FACO, or final assembly and checkout facilities, in Italy and in Japan.

"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," U.S. Air Force Lieutenant Colonel Mike Andrews, a Pentagon spokesman said in a 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."

Meanwhile, at the F-35 FACO plant in Cameri, 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. He added that Lockheed Martin was also restricting employee travel to Cameri citing State Department guidance.

The flu-like virus — which has already killed at least 3,250 people and infected roughly 95,00 people around the world — is emanating from the U.S. Indo-Pacific Command, the largest of all geographic combatant commands.

Last month, the U.S. military said a soldier based in South Korea was the first service member to test positive for the new coronavirus, known as COVID-19.

This week, the nation's top military officer downplayed concerns that the coronavirus poses a significant risk to U.S. service members and the Pentagon's global supply chain.

"Right now the overall broad impact to the uniformed U.S. military is very, very minimal. It's not to say that it's zero, but it's very minimal, very few cases diagnosed, etc.," U.S. Army Gen. Mark Milley, chairman of the Joint Chiefs of Staff, said Monday during a Pentagon news briefing.

"That's not surprising because we have a young demographic, healthy demographic, lots of immunizations, so on and so forth," he said, adding that the department has postponed joint military exercises on the Korean peninsula.

Reuters contributed to this report.