MANCHESTER, New Hampshire (CNN) -- Sen. Barack Obama's spokesman on Saturday accused Sen. John McCain of "cynically running the sleaziest and least honorable campaign in modern presidential campaign history."

Obama, speaking to a crowd Saturday in Manchester, New Hampshire, said, "John McCain wants to have a debate about national security; let's have that debate. I warned that going into Iraq would distract us from Afghanistan. John McCain cheerleaded for it. John McCain was wrong, and I was right."

"The McCain-[Sarah] Palin ticket, they don't want to debate the Obama-Biden ticket on issues because they are running on eight more years of what we've just seen. And they know it," the Democratic presidential nominee said. "As a consequence, what they're going to spend the next seven, eight weeks doing is trying to distract you.

"They're going to talk about pigs, and they're going to talk about lipstick; they're going to talk about Paris Hilton, they're going to talk about Britney Spears. They will try to distort my record, and they will try to undermine your trust in what the Democrats intend to do." Watch more of Obama's comments »

Asked why the campaign's tone was different from its tone during Hurricane Gustav, Obama senior strategist David Axelrod said, "We have enormous concern for people down there ... that's why we canceled 'Saturday Night Live' ... but these people also came out because they're really concerned about the future of the country, and he [Obama] wanted to talk about those issues."

McCain campaign spokesman Tucker Bounds criticized Obama for showing "zero restraint" given the storm and said the "attacks mark a new low from Barack Obama."

The Obama campaign's response was even tougher.

"We will take no lectures from John McCain, who is cynically running the sleaziest and least honorable campaign in modern presidential campaign history," said Obama spokesman Bill Burton. "His discredited ads with disgusting lies are running all over the country today. He runs a campaign not worthy of the office he is seeking."

At the start of his rally, Obama did put politics aside, encouraging the thousands in attendance to think about those in Texas dealing with the fallout from Hurricane Ike. Watch as Hurricane Ike slams into Galveston, Texas »

"I've been on the phone with the head of FEMA and mayor of Houston and others who are trying to grapple with this tremendous storm," he said.

"I know that one of the things that we've seen after Gustav, one of the things that we saw after Katrina and Rita is that during difficult times during moments of tragedy, the American people come together. We may argue, we may differ, but we are all Americans."

The storm prompted the Obama campaign late Friday night to cancel the candidate's appearance on the season premiere of NBC's "Saturday Night Live," saying it was no longer appropriate given what Gulf residents were facing.

Obama's running mate Sen. Joe Biden was supposed to attend the Manchester rally but did not.

Obama is going back to Chicago for the weekend before heading out Monday for Colorado.

Meanwhile, McCain's campaign said a new Spanish language ad set to air in battleground states blames Obama and Senate Democrats for the failure of attempts to overhaul the nation's immigration laws.

"Obama and his congressional allies say they are on the side of immigrants. But are they?" asks the announcer in the 30-second spot, "Which Side Are They On?"

"The press reports that their efforts were 'poison pills' that made immigration reform fail," he continues. "The result: No guest worker program. No path to citizenship. No secure borders. No reform. Is that being on our side? Obama and his congressional allies ready to block immigration reform, but not ready to lead." Watch the ad

But Obama and McCain cast identical votes in the major congressional showdowns on the issue last year.

Both men cast votes in favor of an unsuccessful early June effort to end a filibuster. Later that month, they voted again to end debate on the issue -- but again failed to shut down the filibuster effort, led for the most part by Republican senators.

The ad is set to air in Colorado, New Mexico and Nevada, all crucial states in November with significant Hispanic voting populations.

CNN's Ed Hornick, Sasha Johnson and Rebecca Sinderbrand contributed to this report.

All About John McCain • Barack Obama • FEMA