Japan's Defense Ministry says members of the Japanese Self-Defense Forces on a counter-piracy mission off Somalia have been infected with the coronavirus.
About 180 Self-Defense Force personnel are currently stationed at the mission's base in Djibouti.
The ministry says all personnel were tested after infections were confirmed last Friday and Saturday. An additional 17 personnel tested positive on Wednesday, bringing the total to 21.
The infected personnel are said to be in stable condition and are being quarantined.
Infections were initially reported among support personnel responsible for base security, but the new cases are said to include aircraft crews tasked with patrol and surveillance operations.
The ministry says its mission has not been compromised at this stage because Japan shares patrol and surveillance activities with the United States and other countries.