The tour began in Liverpool, England, and stopped in Jakarta, Indonesia before the journalist tested positive in Kuala Lumpur, Malaysia. The State Department, which had been testing the traveling party daily, said the journalist tested negative in both Liverpool and Jakarta.

Following the Kuala Lumpur visit, Blinken was supposed to spend Wednesday night in Bangkok but ended up just flying in for a “brief logistical layover” before heading back to the U.S.

The journalist who tested positive is still in Kuala Lumpur for the required 10-day isolation. The U.S. Embassy in Kuala Lumpur confirmed in a statement that the individual “was not involved and has not participated in any of Secretary Blinken’s program in Kuala Lumpur.”

State Department spokesman Ned Price said no one else in the traveling party has tested positive so far.

The four-day tour of Indonesia, Malaysia and Thailand was meant to boost relations with Southeast Asia, a “key stage” in the rivalry between the U.S. and China, the Bangkok Post said.

At the airport in Bangkok, at least two Thai ground crew members were seen wearing full protective gear as they serviced Blinken’s plane.

The abrupt change in plans was caused in part by fears that others in the delegation might also test positive, requiring them to quarantine in Thailand over the Christmas holiday.

Price said Blinken spoke with Thai Foreign Minister Don Pramudwinai to explain the change of plans.

“The secretary expressed his deep regret to the FM that he would not be able to visit Bangkok this week. He explained that in order to mitigate the risk of the spread of COVID-19 and to prioritize the health and safety of the U.S. traveling party and those they would otherwise come into contact with the secretary would be returning to Washington, D.C., out of an abundance of caution,” Price said.

In a statement posted online, the U.S Embassy in Kuala Lumpur said it informed the Malaysian government of the virus case and thanked the Malaysian authorities for their support.

“The sole member of the traveling party who tested positive is observing all requirements of the Ministry of Health,” the embassy said. “We can confirm that the person was not involved and has not participated in any of Secretary Blinken’s program in Kuala Lumpur.”

The Associated Press contributed to this report.