Melania Trump's speech writer has admitted making a "mistake" in including comments from a previous address made by Michelle Obama.
Meredith McIver, a Trump Organisation staff writer, said she made an error in including passages from Mrs Obama's 2008 speech to the Democratic National Convention in Mrs Trump's address to the Republican gathering earlier this week.
Ms McIver said she had offered her resignation, but Donald Trump had rejected it.
Explaining her role in the plagiarism controversy, Ms McIver said Mrs Trump read passages of Mrs Obama's speech during the writing the process. She said her notes from that conversation then made it into the final version.
BREAKING: In letter, Meredith McIver accepts responsibility for Melania Trump's speech plagiarism: pic.twitter.com/LFIR5wvamT— Frank Thorp V (@frankthorp) July 20, 2016
Ms McIver said: "I did not check Mrs Obama's speeches. This was my mistake, and I feel terrible for the chaos I have caused Melania and the Trumps, as well as to Mrs Obama. No harm was meant.
"Mr Trump told me that people make innocent mistakes and that we learn and grow from these experiences...
"I apologise for the confusion and hysteria my mistake has cause."
Two passages - each 30 words or longer - of Mrs Trump's initially well-received speech on Monday night matched Mrs Obama's address nearly word-for-word.
The Trump campaign had previously denied accusations of plagiarism, saying the similarities were a coincidence.
Mr Trump's campaign manager Paul Manafort told CNN at the time: ''There's no cribbing of Michelle Obama's speech.
''Certainly, there's no feeling on her part that she did it. What she did was use words that are common words.''