Washington (CNN) Retired physician Ben Carson told Sinclair Broadcasting on Sunday night that he plans to announce his candidacy for president of the United States, but his campaign said Monday he'll reschedule a planned trip to Iowa to say goodbye to his ailing mother.

"I'm willing to be part of the equation, and therefore, I'm announcing my candidacy for president of the United States of America," Carson told Jeff Barnd

He is expected to make the official announcement Monday morning at the Detroit Music Hall Center for the Performing Arts. He had plans to travel to Iowa immediately after the announcement, but campaign spokeswoman Deana Bass said Monday that trip would be rescheduled to allow Carson to fly to Dallas to be with his mother, who suffers from Alzheimer's disease.

"After his announcement in Detroit, Dr. Carson will travel to Dallas to be at his mother Sonya Carson's side. Dr. Carson's mother who has been in failing health is now critically ill," she said in a statement.

The Washington Post , which first reported the news, recounted a tearful Sunday night of preparation and prayer in advance of his Monday morning announcement.

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