SEOUL (Reuters) - The U.S. military command in South Korea said it has instituted a 14-day self quarantine effective Sunday for any troops who recently traveled to China, adding that an outbreak in that country of a new coronavirus could harm military readiness.

United States Forces Korea (USFK) said it knew of no troops who had been in the hardest hit provinces of China, where thousands of people have been infected, and that its quarantine measures were a precaution.

“USFK continues to stress the overall risk to USFK personnel remains low, but that the quarantine measures implemented are out of an abundance of caution to mitigate risk to the USFK population,” the command said in a statement.

The policy only applies to U.S. troops, but the command encouraged military family members, Defense Department civilians, contractors and others to take similar voluntary steps.

In another statement on Saturday, USFK commander General Robert Abrams also said the military assesses the new virus as a low threat, but that it is closely monitoring the spread.

“We must do our best to prevent the spread or it will have a significant impact on our ‘Fight Tonight’ readiness!” he wrote.

On Sunday South Korea reported three more confirmed cases of the new virus, bringing the total in the country to 15. A further 87 people are being tested for possible infection.

The death toll from a coronavirus epidemic in China reached 304 as of the end of Saturday, up by 45 from the previous day, Chinese state TV reported on Sunday.