WASHINGTON (Reuters) - President Barack Obama accused Fox News on Sunday of keeping alive controversies the White House believes have been settled in a testy interview that aired before the NFL's Super Bowl, the most-viewed sports event in the United States.

Host Bill O'Reilly asked Obama why he did not fire his health and human services chief over the botched rollout of the healthcare law last year, whether there was "widespread corruption" at the Internal Revenue Service, and whether the White House had tried to play down the significance of a 2012 attack on the U.S. Consulate in Benghazi, Libya.

Obama said "some boneheaded decisions" were to blame for extra scrutiny the IRS had given to conservative Tea Party groups seeking tax-exempt status, and that the issue had been cleared up during "multiple hearings" in Congress.

"These kinds of things keep on surfacing in part because you and your TV station will promote them," Obama told O'Reilly.

O'Reilly, who hosts a popular program on the most-watched U.S. cable news network, told Obama that many people believed his campaign team sought to downplay the cause of insurgent attacks in Benghazi, which killed four Americans, including U.S. Ambassador Christopher Stevens.

"They believe it because folks like you are telling them that," Obama said, rejecting the allegation, which became a heated issue in the last stages of the 2012 presidential election.

O'Reilly pressed Obama to explain why he did not fire Health and Human Services Secretary Kathleen Sebelius after the website used to enroll people in the new healthcare program known as Obamacare, failed to work during its launch last October.

"My main priority right now is making sure that it delivers for the American people," Obama said, telling O'Reilly that enrollment in health insurance was "about a month behind" projections because of the early problems.

"I promise you that we hold everybody up and down the line accountable," Obama said.

(Reporting by Roberta Rampton; Editing by Peter Cooney)