The Monday speech Melania, Trump's wife, gave at the Republican National Convention had similarities to one first lady Michelle Obama delivered in 2008. It drew widespread criticism and had the Trump campaign playing defense this week amid Trump's official nomination.
McIver said she worked with Melania Trump on her speech and they "discussed many people who inspired her." Trump read McIver passages from Obama's speech at the 2008 Democratic National Convention, and McIver included the phrases.
"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," McIver said.
A Meredith McIver appears as either a contributor or co-author on several Donald Trump books listed on Amazon.com.
Both Donald and Melania Trump shared McIver's statement on their Twitter accounts Wednesday. The GOP nominee criticized the media for its coverage of his wife's speech earlier in the day.
Trump campaign and Republican Party officials have offered a range of defenses for the speech since Monday. Campaign manager Paul Manafort suggested presumptive Democratic nominee Hillary Clinton stirred the controversy.
New Jersey Gov. Chris Christie argued that it was not plagiarism because 93 percent of it was different from Obama's. Republican Party communications director Sean Spicer also made various references to pop culture that used similar phrases.