Democratic vice-presidential candidate Tim Walz acknowledged during a live television debate today that he “misspoke” when he claimed he was in Hong Kong during the 1989 Tiananmen Square massacre. The Minnesota governor faced questioning from a debate moderator who asked why he had consistently stated he was in Hong Kong as Chinese authorities suppressed pro-democracy protests, while he was actually in Nebraska at the time.

In his response, Walz admitted, “I’ve not been perfect, and I’m a knucklehead at times.” This incident is not the first for Walz in this campaign cycle, as he has previously come under scrutiny from fact-checkers.

His opponent on the debate stage, Republican vice-presidential nominee JD Vance, has also made controversial and unfounded claims, including remarks about Haitian immigrants.

During the CBS debate in New York City, the moderator pressed Walz about the timing of his claims regarding the Tiananmen Square protests, which saw Chinese forces kill hundreds, if not thousands, of demonstrators on June 4, 1989. Walz defended his past remarks saying, “All I said on this was, I got there that summer and misspoke on this, so I will just – that’s what I’ve said.”

Walz had previously stated he was in Hong Kong a month before the massacre and subsequently spent a year teaching in mainland China after the events. However, reports indicate that he was actually in Nebraska until August of that year, when he left for China.

The Republican Party has dubbed him “Tiananmen Tim” in light of this controversy. Additionally, the Harris-Walz campaign recently revised Walz’s claims regarding the number of trips he has made to China, correcting his previous assertion of “about 30 times” to “likely closer to 15.”

This isn’t the first time the Harris-Walz campaign has had to clarify statements from Walz. In August, aides issued a correction after Walz had mentioned “weapons of war that I carried in war” while serving in the National Guard, despite never having served in combat. This summer, Walz also stated that he and his wife began their family through IVF, but his wife later clarified that they used a different fertility treatment, intrauterine insemination.