COLUMBUS, Ohio — John McCain yesterday moved to calm rising anger among his supporters at rival Barack Obama, calling him a decent man and at one point taking the microphone away from a woman who called Obama an Arab.

Their anger apparently still at flash point, McCain's supporters then booed him for his conciliatory words about Obama.

The abrupt move from McCain at a town hall meeting in Minnesota came after days of rising tensions as McCain and his campaign attacked Obama as a friend of a 1960s radical they called a terrorist.

Increasingly angry, supporters of McCain and running mate Sarah Palin have responded at rallies with loud cries of "terrorist" and "traitor."

At one such rally earlier this week in New Mexico, McCain visibly winced when his mention of Obama's name was greeted by the shout of "terrorist," but the candidate said nothing about it and went on with his speech.

Supporters at the Minnesota town hall meeting pressed McCain to get even tougher on Obama.

But when one man said he was scared to raise his unborn child in a country that might be led by a President Obama, McCain disagreed.

"I have to tell you, he is a decent person and a person that you do not have to be scared of as president of the United States," McCain said to boos and groans from his supporters.

"If you want a fight, we will fight," McCain said. "But we will be respectful. I admire Senator Obama and his accomplishments. … I don't mean that has to reduce your ferocity, I just mean to say you have to be respectful."

Later, another supporter told McCain, "I don't trust Obama. … He's an Arab."

McCain stood shaking his head as she spoke, then quickly took the microphone from her.

"No, ma'am," he said. "He's a decent family man, a citizen that I just happen to have disagreements with."

Campaigning in Ohio hours before, Obama defended his character against the mounting attacks, daring McCain to run as negatively as he wants in the final weeks of the race while predicting that, in light of the financial crisis, "it will not work."

Both candidates responded to the stock market meltdown with new policy proposals. McCain, in Wisconsin, suggested waiving a tax rule requiring that investors begin selling off their IRAs and 401(k)s when they turn 701/2. Obama, in Ohio, pitched temporarily lifting lending fees and extending fixed-rate loans to small businesses through a Small Business Administration disaster relief fund.

But the dramatic personal nature of the campaign overshadowed those developments.

"We know what's coming, we know what they're going to do," Obama told supporters in Chillicothe and later in Columbus.

McCain's campaign had announced a national TV ad that asserts Obama worked with a "terrorist" when it was politically convenient and then lied about their relationship.

The man, Bill Ayers, is a professor of education at the University of Illinois-Chicago who in 1995 hosted a candidate event for Obama and was involved with two mainstream charitable groups in which Obama also had been active. Chicago Mayor Richard Daley has praised Ayers as a leading citizen who helped shape the city's innovative schools program.

In the late 1960s and early '70s, when Obama was a child, Ayers belonged to the radical antiwar group Weather Underground, which advocated violence and placed bombs at the Pentagon and the Capitol.

McCain's accusation is that Obama understated what he knew about Ayers' past or his beliefs when it suited him. There's no evidence that the two men are close or that Ayers has any connection to Obama's presidential campaign.

At a rally on Thursday, McCain himself used the word "terrorist" to describe Ayers, and many McCain supporters were whipped into a lather as they voiced fear and indignation at Obama's ascent. Many participants chanted "liar, liar" when Obama's name was mentioned.

However, at a rally yesterday morning in La Crosse, Wis., McCain seemed to dial back the tone. He didn't mention Ayers, and perhaps his most negative words were to paint Obama as "a Chicago politician."