President Donald Trump ridiculed former Vice President Joe Biden Tuesday for a series of campaign gaffes: repeatedly forgetting which state he was campaigning in.

“Hey, have you ever noticed where Biden keeps saying he’s in the wrong state?” Trump asked supporters at a campaign rally in Hershey, Pennsylvania.

Biden has been caught on tape twice referring to Ohio when he was Iowa, and when he was in New Hampshire, saying he was in Iowa or Vermont. And even mixing up Iowa and Vermont.

“What is wrong with this guy? What’s wrong with him?” Trump asked. “There’s something wrong … how many times can you do that?”

Trump reminded Pennsylvania voters that Biden vowed to shut down fossil fuel production, which would dramatically affect workers in Pennsylvania.

“The voters of this commonwealth will never ever let that happen,” Trump said, as the crowd cheered.

The president also mocked Biden for putting up his hand when debate moderators asked candidates if they would commit to allowing medical coverage for illegal immigrants.

“He just raises his hand, he has no clue what he’s doing. Remember [how] he looked?” Trump asked, noting that Biden was just following the rest of the crowd on the stage.

Biden told Axios on Sunday that he sometimes gets his words tangled up or finds himself searching for the right word when he is tired.

“I’ve always attributed that to being tired and not to the stutter,” he said. “I don’t think of myself as continuing to stutter.”