“Earlier this evening, the Vice President’s traveling delegation was delayed from departing Singapore because the Vice President’s office was made aware of a report of a recent possible anomalous health incident in Hanoi, Vietnam,” according to a statement posted to the U.S. embassy in Hanoi’s website.

Additional details were not immediately available.

Anomalous health incidents is the phrase the U.S. government uses to classify the mysterious brain injuries, referred to as "Havana syndrome," first reported by U.S. officials stationed in Cuba. Dozens of cases have been reported elsewhere, though the official cause of the affliction remains unsettled.

Symone Sanders, a spokesperson for Harris, told reporters aboard Air Force Two that the delay "has nothing to do with the vice president's health."

"She is well, all is fine and looking forward to meetings in Hanoi tomorrow,” Sanders said.

Earlier Tuesday the vice president gave a speech condemning the Chinese government’s actions in the South China Sea and reaching out to other countries in Asia.

“Our engagement in Southeast Asia and Indo-Pacific is not against any one country, nor is it designed to make anyone choose between countries,” she said. “Instead, our engagement is about advancing an optimistic vision that we have for our participation and partnership in this region."

Harris’ previous international trip was overshadowed by the specter of the situation at the U.S.-Mexico border, an area that has bedeviled the Biden administration since taking office in January.

Harris is due to become the first vice president to visit Vietnam since North and South Vietnam were reunited in 1975. Previous vice presidents Lyndon Johnson and Richard Nixon visited Saigon, the capital of South Vietnam, prior to reunification.