WASHINGTON (AFP) — Republican White House hopeful John McCain lashed out at Barack Obama Sunday over the Democrat’s links to a 1960s radical whom McCain called an “unrepentant terrorist.”

The maverick Arizona senator also denied he was out of touch with the nation’s economic plight, and said his fiery temper was no disqualification from serving as president.

McCain said he was sure Obama was “very patriotic” but said his relationship with William Ayers, a University of Illinois professor who was once part of the violent Weather Underground group, was “open to question.”

Obama said last week his relationship with Ayers went no further than sitting on a Chicago charity board together, as the Illinois senator rebuffed attacks on his patriotism and condemned Weather Underground as “detestable.”

Obama’s rival for the Democratic nomination, Hillary Clinton, highlighted the Ayers link last week during a televised debate, and McCain told ABC television that the professor was an “unrepentant terrorist.”

In 2001, Ayers said of the far-left militants of Weather Underground, which bombed government buildings from 1969 to 1975, “I feel we didn’t do enough.”

In the debate, Obama said he was also friends with Republican Senator Tom Coburn, who once called for the death penalty for doctors who carry out abortions. “Do I need to apologize for Mr. Coburn’s statements?” he said.

McCain said Obama’s evocation of Coburn, a doctor who continues to deliver babies, in this context was “very insulting” and “borders on outrageous.”

Obama campaign spokesman Bill Burton issued a blistering statement in response.

“Unable to sell his out-of-touch ideas on the economy and Iraq, John McCain has stooped to the same smear politics and low road that he denounced in 2000,” he said referring to McCain’s failed presidential bid eight years ago.

“The American people can’t afford a third term of President (George W.) Bush’s failed policies and divisive tactics,” he said.

McCain was hit by a new Democratic Party ad accusing him of having no idea about the nation’s economic plight.

“Times are very, very tough. And the worst thing you can do, the worst thing you can do is raise taxes. Both Senator Clinton and Senator Obama want to raise taxes. That’s out of touch,” he said on ABC.

McCain added he was the “worst nightmare” of Washington insiders and big spenders on both sides of the political aisle, pledging anew to veto any expenditure bill containing pork-barrel projects if elected president.

The senator swatted aside questions over his temperament, after a front-page Washington Post story reviewed his many incendiary clashes with political rivals and colleagues down the years.

“I love what we stand for and believe in, and many times I deal passionately when I find things that are not in the best interests of the American people,” he said, while dismissing such articles as untrue or “grossly exaggerated.”

The Republican nominee-elect was pressed on his own endorsement by the Reverend John Hagee, an evangelical pastor who has made outspoken remarks attacking the Roman Catholic Church.

McCain said it was “probably” a mistake to solicit Hagee’s endorsement, which might help him with evangelical voters, but said he was “glad” to have it nonetheless.

“I said any comments that he made about the Catholic Church I strongly condemn, of course,” he said.