MR George Mitchell has dismissed as "completely false" a headline in a Washington newspaper that he has returned to the United States "rebuffed in talks on Northern Ireland", Joe Carroll reports from Washington.
Mr Mitchell told The Irish Times yesterday he was leaving, Washington shortly on a business trip but would be returning to Belfast to resume his chairman's role on Tuesday.
The former Finnish prime minister, Mr Harri Holkeri, will replace him on Monday.
"When I took on this assignment as a volunteer I made it clear to the governments that I had certain business commitments to honour and would have to come back to the United States from time to time," Mr Mitchell said.
He said he was "committed to the process and looking forward to getting back there". He hoped that the discussions on the rules procedures could be completed next week so substantive talks could begin. A decision had not yet been made on a date for the next plenary session.
The Washington Times report from the AP news agency said Mr Mitchell "headed home yesterday uncertain when or how he could win the confidence of Protestants who accuse him of favouring the Irish Republican Army's allies in talks on the future of Northern Ireland".
The report said: "Protestant leaders have proposed reducing Mr Mitchell's role and boosting the involvement of Mr Mitchell's Canadian colleague, Gen John de Chastelain, whom they consider more important".