When a company of Royal Thai Army soldiers quarantined after returning home from training in Hawaii, 11 were isolated when they exhibited flu-like symptoms. Now Thai authorities say eight have tested positive for COVID-19.

They had been training with members of the 25th Infantry Division’s 2nd Infantry Brigade Combat Team during Exercise Lightning Forge as part of the Army’s Pacific Pathways program. Through that initiative the 25th Infantry Division has been training extensively with Thai troops over the past year.

Members of the U.S. Army’s newly formed 5th Security Force Assistance Brigade based at Joint Base Lewis McChord in Washington state also came to Hawaii for the exercise.

It was the army’s first brigade level exercise since the beginning of the pandemic. During the exercise all participants — about 5,500 troops — were kept in a “training bubble” to prevent infections. Thai troops were kept in military housing and training facilities.

During the exercise five U.S. troops were sent to Tripler when they exhibited potential symptoms but all tested negative. U.S. Army officials in Hawaii have been in contact with the American Embassy in Thailand and Thai military officials as they try to determine where and how the visiting soldiers contracted the virus.

“We are evaluating the force health protection measures that were put in place during Lighting Forge and have implemented contact tracing and increased testing among our soldiers to help determine the overall health assessment of our forces following the exercise,” said 25th Infantry Division spokesman Lt. Col. Adam Hallmark.

Due to orders from the Pentagon, Hawaii-based military commanders can’t release infection numbers publicly but share data with Hawaii state health officials. The total case numbers for Hawaii include military infections, but state officials don’t publicly distinguish military and civilian cases.

Thailand currently has had a total of 3,297 cases, 3,111 of whom recovered while 128 remain in hospitals, with a death toll of 58. The same Thai soldiers are scheduled to return this fall as part of Pacific Pathways to train again with the 2nd Brigade at Fort Polk, Louisiana.