(CBS) — Former Donald Trump campaign manager Corey Lewandowski said someone on the campaign staff should be held “accountable,” after Melania Trump’s speech to the Republican National Convention appeared to plagiarize part of Michelle Obama’s 2008 speech to the Democratic National Convention.

Melania Trump’s speech at the opening night of the convention Monday in Cleveland won praise for its positive message, and lack of political attacks that have characterized much of her husband’s bid for the White House.

However, part of her speech bore a striking resemblance to a segment of Michelle Obama’s speech eight years ago.

Melania Trump at 2016 RNC:

“My parents impressed on me the values that you work hard for what you want in life; that your word is your bond, and you do what you say, and keep your promise; that you treat people with respect. They taught and showed me values and morals in the daily life. That is the lesson that I continue to pass on to our son, and we need to pass those lessons on to the many generations to follow; because we want our children in this nation to know that the only limit to your achievement is the strength of your dreams, and your willingness to work for them.”

Michelle Obama at 2008 DNC:

“Barack and I were raised with so many of the same values — like you work hard for what you want in life; that your word is your bond, that you do what you say you’re going to do; that you treat people with dignity and respect, even if you don’t know them, and even if you don’t agree with them. And Barack and I set out to build lives guided by these values, and to pass them on to the next generation, because we want our children — and all children in this nation — to know that the only limit to the height of your achievements is the reach of your dreams, and your willingness to work for them.”

Lewandowski said, if anyone is to blame, it’s Donald Trump’s staff, not his wife.

“I think Mrs. Trump’s a very smart, articulate woman. Her thoughts are her own thoughts, and I think if there was a mistake, it was at the staff level, and the staff should be held accountable,” he said Tuesday morning after speaking at the RNC.

Melania Trump has said she wrote the speech with little help, but Lewandowski insisted a campaign staffer should have vetted it before she spoke.

“Again, what I said was I think Melania Trump is an extremely smart and articulate woman, and the outline of that speech is her own, and she put those thoughts together so she could talk about her husband, and if the staff didn’t vet the speech properly, what thoughts were put together, and the person who wrote that speech, they should be held accountable, there’s no question about that,” he said.

Lewandowski declined to say if anyone on the Trump campaign should be fired, saying it’s up to whoever is in charge.

Illinois congressman Peter Roskam hit back at vice president’s Joe Biden, telling WBBM’s Craig Dellimore, “Joe Biden has a lot of experience in this with his own plagiarism in the past. It cost him his presidential campaign a number of years ago.

The Obama-Biden team and the Clintons “are familiar with his narrative,” he said.

Former Obama senior adviser David Axelrod called Melania Obama’s speech outright plagiarism.

“Whoever did that was grossly irresponssible,” he said on CNN, wondering, “How could anyone be so fundamentally stupid?”

Trump campaign Senior Communications Advisor Jason Miller issued a statement saying, “In writing her beautiful speech, Melania’s team of writers took notes on her life’s inspirations, and in some instances included fragments that reflected her own thinking. Melania’s immigrant experience and love for America shone through in her speech, which made it such a success.”