President Obama said he  "relies heavily" on his Christian faith as president during a press conference on Friday.

Polls recently showed an increasing number of Americans erroneously believe that Obama is a Muslim.

Obama invoked his religion in response to a question about several recent national controversies about Islam. 

"As someone who relies heavily on my Christian faith in my job, I understand the passions that religious faith can make," Obama said Friday, reacting to a question about controversies over a proposed Islamic center near the site of the 9/11 attacks, and a Florida pastor's now-cancelled plans to burn copies of the Quran tomorrow.

The president said the passions stirred recently over Islam reflect the general anxiety Americans are experiencing in a down economy.

"I think that at a time when the country is anxious generally and going through a tough time, then fears can surface — suspicions, divisions can surface," he said.

Obama also credited his predecessor, Republican President George W. Bush for having emphasized after 9/11 that the U.S. is not anti-Islam. 

"One of the things that I most admired about President Bush, was after 9/11 him being crystal clear about the fact that we are not at war with Islam," Obama said.

The president vowed to do everything in his power to promote religious tolerance.

"I will do everything that I can … to remind the American people that we are one nation, under God. We may call that God different names, but we remain one nation," Obama said.

Eighteen percent of Americans said in a Pew Research Center poll that they believe Obama is a Muslim. Thirty-four percent correctly identified him as a Christian, while 43 percent of Americans said they didn't know what faith the president practices.

That poll was conducted July 21-Aug. 5.