MASON CITY, Iowa — Democrat Barack Obama on Sunday confronted one of the persistent falsehoods circulating about him on the Internet.

He went to church.

His attendance here at the First Congregational United Church of Christ, with the news media in tow, was as much an observation of faith as it was a rejoinder to the e-mailed rumors that he is a Muslim and poses a threat to the security of the United States.

Obama did not address the rumors, but described how he joined Trinity United Church of Christ in Chicago two decades ago while working as a community organizer.

"What I found during the course of this work was, one, that ordinary people can do extraordinary things when they come together and find common ground," he told the congregation. "The other thing I discovered was that values of honesty, hard work, empathy, compassion were values that were spoken about in church .... I realized that Scripture and the words of God fit into the values I was raised in."

Obama is known to invoke religious references in his speeches and has said he has a "personal relationship" with Jesus Christ. He often has said that religion has a place in public life and that faith and politics are not exclusively the domain of conservatives.

"During this holiday season and during this political season I'm continually reminded that the values that I learned at Trinity and as part of the UCC community are values that can't just stay in church but have to be applied outside of church," he said.

Obama staffers and volunteers say they periodically encounter voters who say they cannot support Obama because he is Muslim, a claim that has been making its way through Internet sites and blogs since he announced his candidacy for president. Aides say he regularly attends church on Sundays, even while on the road, but without the news media watching.

Earlier this month, Hillary Rodham Clinton's campaign forced the resignation of two Iowa volunteer coordinators who had forwarded e-mails that tried to tie him to Islamic jihadists.

The Illinois Democrat — whose middle name is "Hussein" — was born in Hawaii and moved to Indonesia at age 6 to live with his mother and stepfather, who was Muslim. He left Indonesia when he was 10 and returned to Hawaii to live with his mother's parents.

Obama sat in a pew accompanied by Joann Hardy, one of his Mason City precinct captains, and her husband, Russ, and their family.

He also participated in a church tradition of tossing mittens onto a bare Christmas tree. He joked that as a basketball player, the toss should not pose much of a challenge.

His first underhand throw hit mid-tree. His second was close to the top, and elicited a cheer. But his mitten was quickly overwhelmed by colorful hats, scarves and gloves tossed onto the tree by the other congregants.

Later, Obama shifted to the secular, detailing his plan for tax relief for the middle class and for seniors with incomes of less than $50,000 a year.