Mitch McConnell, the top Republican in the US Senate, froze up for more than 30 seconds on Wednesday during a media briefing before he was escorted away, in the second such incident in a little more than a month.
Mr McConnell, 81, was responding to questions after an event with the Northern Kentucky Chamber of Commerce in Covington when he froze up, staring into space and not responding, a clip from a local news station showed.
After being approached by an aide, he began talking again, but needed questions to be repeated and gave minimal answers.
A representative of Mr Connell later said the Senate minority leader “felt momentarily light-headed” and would consult with a physician before more public events.
President Joe Biden later commented on the incident at the White House, saying that “Mitch is a friend”.
“I'm going to try to get in touch with him later this afternoon,” he added.
The incident was similar to one that took place in the Senate at the end of July, when Mr McConnell also froze in the middle of a media briefing and had to be led away, returning minutes later to finish taking questions.
He suffered a concussion from a fall earlier this year, which required time in hospital.
Reuters contributed to this report