Democratic presidential candidate Barack Obama said Thursday that Republican John McCain was "losing his bearings" for repeatedly suggesting the Islamic terrorist group Hamas preferred Obama for president.

That brought an angry response from McCain's campaign, which accused Obama of trying to make an issue of McCain's age.

Age is a touchy subject for McCain, who turns 72 in August and would be the oldest person to be sworn in as president if elected.

The two senators have focused more intently on one another in recent weeks as Obama has moved closer to becoming the Democratic nominee. Thursday's back and forth between Obama and surrogates for both candidates foreshadowed a likely argument for the fall campaign.

The sparring also comes the same week as Obama's decisive victory in North Carolina's primary, which brought renewed calls for Hillary Rodham Clinton to get out of the race and clear a path for him to claim the Democratic nomination and focus on McCain.

At the root of the dispute is McCain's decision to call attention to a Hamas adviser's apparent affinity for Obama. The adviser, Ahmed Yousef, said in a recent interview: "We like Obama and hope that he will win the election."

McCain used those comments in a fundraising appeal and has cited them in interviews.

Asked about the matter Wednesday during a taping of "The Daily Show with Jon Stewart," McCain said: "It's indicative of how some of our enemies view America. And I guarantee you, they're not going to endorse me."

In an interview Thursday with CNN, Obama accused McCain of trying to smear him by repeating the comments.

"This is offensive, and I think it's disappointing, because John McCain always says, 'Well, I'm not going to run that kind of politics,'" Obama said. "And then to engage in that kind of smear, I think, is unfortunate, particularly since my policy toward Hamas has been no different than his."

The Illinois senator added: "For him to toss out comments like that, I think, is an example of him losing his bearings as he pursues this nomination. We don't need name-calling in this debate."

Like McCain, Obama criticized former President Carter for recently meeting with Hamas leaders, saying the U.S. must not negotiate with a terrorist group that is intent on Israel's destruction. McCain had called on Obama to repudiate Carter's meeting.

McCain's campaign issued an angry response that accused Obama of trying to divert attention from a legitimate question by raising McCain's age.

"He used the words 'losing his bearings' intentionally, a not-particularly-clever way of raising John McCain's age as an issue," McCain adviser Mark Salter said. "It is more than fair to raise this quote about Senator Obama, because it speaks to the policy implications of his judgment."

Obama spokesman Bill Burton insisted that Obama was not trying to do what McCain's campaign accused him of.

"Clearly, losing one's bearings has no relation to age," he said.

Thus far, Democrats have been careful not to mention McCain's age, at least not directly. The lone exception is Rep. John Murtha, D-Pa., a supporter of Hillary Rodham Clinton who a few weeks ago said the rigors of running the country is too much for guys their age.

"Let me tell you something, it's no old man's job," Murtha, 75, told a union audience.

In response, McCain told CNN: "All I can tell you is that I admire and respect Jack Murtha. Speak for yourself, Jack. I'm doing fine. Thanks."