President Donald Trump says he hopes an aide who resigned this week in the wake of domestic abuse allegations has “a great career ahead of him.”

Trump told reporters at a surprise appearance Friday that former White House Staff Secretary Rob Porter did “a very good job while he was in the White House” and adds: “We wish him well.”

Porter has been accused of domestic abuse by two ex-wives and a former girlfriend. He has denied the charges.

Trump said he was surprised by the abuse allegations and called the news “very sad.”

Trump also stressed that Porter maintains he is innocent. He says: “I think you have to remember that.”

He made no mention of the women in his comments, which were prompted by a reporter's question.

"We wish him well," the president said. "He worked very hard. I found out about it recently and I was surprised by it. But we certainly wish him well. It's obviously a tough time for him. He did a very good job when he was in the White House. And we hope he has a wonderful career, and hopefully he will have a great career ahead of him. But it was very sad when we heard about it, and certainly he's also very sad. Now he also as you probably know, he says he's innocent. And I think you have to remember that. He said very strongly yesterday that he's innocent. So you'll have to talk to him about that. But we absolutely wish him well. Did a very good job while he was at the White House."

The allegations about Porter and the White House's response to them have rocked the White House. Jennie Willoughby, Porter's second wife, filed an emergency protective order against him, and his first wife, Colbie Holderness, said he kicked her and displayed images of a black eye she says she received from him punching her.

The White House was aware of the allegations against Porter long before the Daily Mail first published the allegations on Tuesday.

(The Associated Press, CBS News contributed to this report.)