President Barack Obama said he is not worried about a recent poll showing that nearly one-fifth of Americans believe he is a Muslim.

"The facts are the facts," said Mr Obama, who is a Christian.

In an interview broadcast on NBC Nightly News, the president blamed the confusion over his religious beliefs on "a network of misinformation that in a new media era can get churned out there constantly".

A poll released earlier this month by the non-partisan Pew Research Centre showed that 18% of people believe Obama is Muslim.

That was up from 11% who said so in March 2009. Just 34% said Mr Obama is Christian, down from 48% who said so last year.

"I'm not gonna be worrying too much about whatever rumours are floating on out there," Mr Obama said. "If I spend all my time chasing after that, then I wouldn't get much done."

Asked about persistent accusations that he was not born in the United States, the president responded: "I can't spend all my time with my birth certificate plastered on my forehead."