Democratic presidential candidate Hillary Clinton said on Friday she was sorry that her use of a personal email account while secretary of state had caused confusion, and blamed herself for "not thinking a lot" about the matter when she took the job.

In her most contrite comments yet about an issue that has plagued her White House bid, Clinton said she had made a mistake by not using a government email account. But she maintained she had done nothing wrong and did not apologize explicitly for using a private email account for her work as America's top diplomat.

"At the end of the day I am sorry that this has been confusing to people and has raised a lot of questions but there are answers to all these questions," the former first lady told MSNBC in an interview.