Forty-nine percent of voters identify President Obama as a Christian, a new poll says, and the others say that they don't know or that he is a Muslim.

"Nearly four years into his presidency the view that Barack Obama is Muslim persists," says the survey from the Pew Research Center's Forum on Religion & Public Life.

According to the poll on religion and politics, 17% say Obama is a Muslim, while 31% say they do not know his religion.

"Fewer say Obama is Christian -- and more say he is Muslim -- than did so in October 2008, near the end of the last presidential campaign," Pew reported. "The increase since 2008 is particularly concentrated among conservative Republicans, about a third of whom (34%) describe the president as a Muslim."

The survey -- also conducted by the Pew Research Center for the People & the Press -- further reported that voters are unconcerned about the Mormon faith of Republican candidate Mitt Romney, our On Politics blog reports.

Pew reports: