Republican Senate leader Mitch McConnell is “medically clear” to work, says a doctor, a day after the lawmaker suddenly appeared unable to speak for the second time this summer.

Brian Monahan, the attending physician of the US Congress, said he had consulted with Mr McConnell and his neurology team about the matter.

On Wednesday, Mr McConnell, 81, froze up for more than 30 seconds when asked if he would run for re-election.

He had a similar lapse in July.

During Wednesday’s press event in Covington, Kentucky, the senator was unable to answer questions, which had to be repeated by staff.

Mr McConnell made no comment about his health before leaving with aides, who later said he was feeling lightheaded.

He suffered from a concussion after falling at an event in March, according to staff.

Dr Monahan said in a statement on Thursday: “Occasional lightheadedness is not uncommon in concussion recovery and can also be expected as a result of dehydration.”

Politico reported that a handful of Republican senators were weighing whether Mr McConnell should stay on as leader.

Republican congresswoman Marjorie Taylor Greene, meanwhile, wrote in a post on social media that Mr McConnell was “not fit for office.”

“Severe aging health issues and/or mental health incompetence in our nation’s leaders MUST be addressed,” Ms Greene said, also mentioning the age of US President Joe Biden, who is 80.

Democratic congressman Dean Phillips called on social media for term limits for members of Congress and the Supreme Court.

On Thursday, President Joe Biden said he had recently spoken with Mr McConnell and that he seemed well.

“He’s a friend, and I spoke to him today. And you know, he was his old self on the telephone,” Mr Biden told reporters in Washington DC.

Mr Biden added he did not have any concerns about whether Mr McConnell was fit enough to do his job.