The person who wrote Melania Trump’s speech to the Republican convention should “probably” be fired, the Republican National Committee chairman said on Tuesday, after accusations that plagiarised parts of the address from Michelle Obama.

Reince Priebus said he did not blame Donald Trump’s wife for the controversy and that some of the themes of the speech were “pretty common”. But he seemed to concede that the issue had disrupted the convention.

“The distraction gets you off message a little bit this morning, but I think we’ll get back to action this afternoon,” he told a Bloomberg Politics event.

Mr Priebus’s suggestion that heads should roll was echoed by Corey Lewandowski, Mr Trump’s former campaign manager, who said his successor, Paul Manafort, should quit if he had approved the speech.

“Whoever … was the final sign-off that allowed this to go forward should be held accountable … I think if it’s Paul Manafort he’d do the right thing and resign,” Mr Lewandowski told CNN.

The Trump campaign denies that Mrs Trump took words from Mrs Obama’s speech to the 2008 Democratic convention, but several parts of the Slovenia-born former model’s speech were similar. Some phrases — including “you work hard for what you want in life, that your word is your bond and you do what you say” — were identical.

In response to the accusations of plagiarism, Jason Miller, the Trump campaign spokesman, said: “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.”

Chris Christie, the New Jersey governor and former prosecutor, told NBC’s Today he could not make the case for plagiarism — “not when 93 per cent of the speech is completely different than Michelle Obama’s speech.”