An aide for Republican presidential nominee Donald Trump said Wednesday she took responsibility for copying portions of First Lady Michelle Obama's 2008 address for Melania Trump's convention speech on Monday.

Staff writer Meredith McIver, who called herself "a longtime friend and admirer of the Trump family," said in a statement released by the Trump campaign that while working with Mrs. Trump on her First Lady speech, the two discussed many people who inspired Mrs. Trump.

"A person she (Melania Trump) has always liked is Michelle Obama," said McIver. "Over the phone, she read me some passages from Mrs. Obama's speech as examples. I wrote them down and later included some of the phrasing in the draft that ultimately became the final speech."

According to McIver, she did not check Mrs. Obama's 2008 speech.

"This was my mistake, and I feel terrible for the chaos I have caused Melania and the Trumps, as well as to Mrs. Obama," said McIver, adding that her offer to resign was rejected by the Trump family.

The statement came two days after embarrassing similarities were revealed between parts of Mrs. Trump's speech at the 2016 Republican National Convention on Monday night and Mrs. Obama's 2008 convention speech.

The plagiarism charges threatened to overshadow Trump's official ascent to the standard-bearer of a major US political party, and came just hours after the Trump campaign fiercely denied the overlap.

Shortly after the release of the statement, Trump pointed out one positive side of the episode in his twitter post that his wife's speech "got more publicity than any in the history of politics especially if you believe that all press is good press."

In another twitter post, Trump criticized the US media for spending more time "doing a forensic analysis of Melania's speech than the FBI spent on Hillary's emails."