PUEBLO, Colo. » Mitt Romney led a chorus of Republican criticism of the administration’s foreign policy today, accusing President Barack Obama of minimizing the recent killing of the U.S. ambassador to Libya as a mere "bump in the road" rather than part of a chain of events that threatens American interests.

White House press secretary Jay Carney called the accusations "desperate and offensive," an attempt by Romney and his allies to gain political advantage in the latter stages of a political campaign that seems to be trending the president’s way.

Obama flew from the White House to New York, one day before he speaks to world leaders at the opening of the annual session of the United Nations General Assembly. He and first lady Michelle Obama also booked an appearance on television’s "The View."

The back and forth on foreign policy occurred as Romney said he was shifting to a more energetic schedule of public campaign events, bidding to reverse recent erosion in battleground state polls. After days spent largely raising campaign cash — and trying to minimize the fallout from one speech to donors last spring — he pledged to make the case for "real and positive change."

While national polls make the race exceedingly close, Obama has gained ground on Romney in many recent surveys when potential voters are asked to compare the two rivals in their ability to fix the economy. Sluggish growth and national unemployment of 8.1 percent make the economy by far the dominant issue in the race, and the two men have focused much of their time and advertising budgets on highlighting their differences on taxes, spending and plans for job creation.

The same polls show Obama with a healthy lead over Romney when voters are asked which candidate is better equipped to handle foreign policy, and the president has not shied away from trumpeting his decision to order the secret mission by U.S. forces that killed terrorism mastermind Osama bin Laden in his Pakistani hideout more than a year ago.

At the same time, Romney’s advisers say voters are more inclined to question Obama’s handling of foreign policy after the attack on the U.S. consulate in Benghazi, Libya, earlier this month resulted in the death of the U.S. ambassador and three other Americans.

Not only Romney, but other Republicans, as well, challenged Obama on foreign policy today.

In a conference call with reporters, Rep. Eric Cantor, R-Va., the House majority leader, said, "Israel continues to find itself on the receiving end of harsh language by the president of the White House. … There is a somewhat continued pattern of throwing Israel under the bus when Israel stands as our closest ally."

And the National Republican Senatorial Committee issued challenges to Democratic candidates in several races to "share their view" on Obama’s remarks in an interview with CBS’ "60 Minutes" over the weekend.

In the interview itself, Obama was responding when asked if recent events in the Middle East gave him pause for supporting governments that came to power following a wave of regime changes known as the Arab Spring.

He said he has long noted that events were going to be rocky, adding that the question itself "presumes that somehow we could have stopped this wave of change."

"I think it was absolutely the right thing for us to align ourselves with democracy, universal rights. … But I was pretty certain and continue to be pretty certain that there are going to be bumps in the road because — you know, in a lot of these places — the one organizing principle has been Islam. …

"There are strains of extremism, and anti-Americans, and anti-Western sentiments and you know can be tapped into by demagogues," he added.

Romney was eager to talk about the topic, squeezing interviews with three television networks into his schedule and touching on the subject at the beginning of a rally in Pueblo, Colo.

"I can’t imagine saying something like the assassination of ambassadors is a bump in the road, when you look at the entire context, the assassination, the Muslim Brotherhood president being elected in Egypt, 20,000 people killed in Syria, Iran close to becoming a nuclear nation, that these are far from being bumps in the road," he told ABC.

"They represent events that are spinning out of the kind of influence we’d like to have. We’re at the mercy of events rather than shaping the events in the Middle East."

U.S. officials are investigating the deaths in Libya, which occurred when the consulate was breached.

Obama has said extremists used an anti-Islam video as an excuse to assault U.S. interests overseas, including the incident in Benghazi.

Romney intends to return to the subject of international affairs and discuss foreign aid, trade agreements and international development when he addresses the Clinton Global Initiative in New York on Tuesday, according to a person familiar with the campaign’s thinking.

Romney, like Cantor, took a slap today at Obama’s handling of relations with Israel.

"The president doesn’t have time to actually spend time with leaders of these nations, particularly Bibi Netanyahu, I find that very troubling," he said.

In a campaign setting records for television advertising, both campaigns released new commercials during the day.

Obama’s latest seeks to extend the controversy that erupted when Romney was seen on video saying that, as a candidate, he doesn’t worry about the 47 percent of Americans who he said pay no income tax and see themselves as victims deserving of a wide range of government benefits.

"Maybe instead of attacking others on taxes, he should come clean on his," says the 30-second commercial, airing in battleground Ohio.

Romney last week released his 2011 tax return, showing he paid $1.94 million in federal taxes on income of $13.7 million. The 14.1 percent rate is less that millions of American families pay because Romney’s earnings come from capital gains and dividends, which are taxed at a lower rate than wages.

Romney’s new ad shows a shuttered factory and says fewer Americans are working these days. It accuses the president of failing to stand up to China in matters of trade, and says the Asian nation steals "American ideas and technology … everything from computers to fighter jets."

Associated Press writer Philip Elliott contributed from Washington. Espo reported from Washington.