Attorney General William Barr's claim he thought President Donald Trump's 2016 presidential campaign was spied on is "both stunning and scary," the former Director of National Intelligence said Wednesday during an appearance on CNN.

"I thought it was both stunning and scary," said James Clapper, who served under President Barack Obama. "I was amazed at that and rather disappointed that the attorney general would say such a thing. The term 'spying' has all kinds of negative connotations, and I have to believe he chose that term deliberately."

Barr, appearing before a Senate panel hearing, declared Wednesday he believes "spying did occur" on Trump's campaign, suggesting the origins of the Russia probe might have been mishandled.

Barr said he did not have specific evidence of wrongdoing but told the panel he did "have questions about it."

"I think spying on a political campaign is a big deal," Barr added.

Asked by Sen. Jeanne Shaheen, D-N.H., if he believed spying on the campaign occurred, Barr said, "Yes I think spying did occur. The question is whether it was adequately predicated."

Asked again about spying at the end of the hearing, Barr tempered his tone "I am not saying improper surveillance occurred," he said. "I am saying I am concerned about it, and I am looking into it."

Clapper criticized Barr for making the comments.

"It would have been far more appropriate for him to just defer to that investigation rather than postulating with apparently no evidence," he told CNN’s Anderson Cooper. "He just has a feeling that there was spying against the campaign."