WASHINGTON -- Republican presidential nominee Mitt Romney is looking to recover from a tough week dominated by foreign policy as President Barack Obama balances campaigning for a second term with facing the spread of anti-American violence in the Muslim world.

Obama led the nation in a sombre homecoming Friday for four Americans killed in a brazen attack on the U.S. Consulate in Benghazi, Libya, as his election opponents argued they would have done a better job preventing crisis from erupting overseas.

With anti-U.S. protests spreading, Obama sought Friday to offer both compassion as president and firm resolve as commander in chief to protect besieged American interests abroad. Polls have shown most voters consider Obama a steady international leader, and the ongoing unrest abroad is challenging him to prove he deserves that confidence.

Romney also faced a delicate test. With momentum in the tight race recently going toward Obama, Romney sought to keep up sharp campaigning without appearing to divide the nation and unnecessarily attacking the commander in chief at a time of crisis.

Romney is trying to reassure concerned conservatives he has a winning strategy that hinges, at least in part, on strong performances at next month's debates. But he will also unveil an aggressive push to expand his support among women and Hispanics, key groups that both sides are courting heavily.

On Saturday, Obama launched an aggressive new TV ad campaign to convince voters in the most competitive states that Romney is risky for the nation's economic recovery with a plan that caters to multimillionaires over the middle class.

"They want to go back to the same old policies that got us in trouble in the first place," former President Bill Clinton is shown saying in the 60-second TV ad set to run in Colorado, Florida, Iowa, New Hampshire, Nevada, Ohio, and Virginia. Obama's campaign spent about $6 million to buy airtime for the new ad.

"We're not going back, we are moving forward," Obama adds in the commercial.

Romney doesn't agree, and says the U.S. is not better off after nearly four years of Obama's leadership of a nation with the unemployment rate stubbornly stuck around 8 per cent. The former business executive argues that he is best suited to fix the sluggish economy.

"All the false and misleading ads in the world can't change one simple fact: Americans are not better off since President Obama took office," said Ryan Williams, a Romney campaign spokesman.

The new Obama push, coupled with ads this past week by both candidates squaring off over China's impact on the U.S. economy, comes seven weeks before Election Day, and as polls point to modest gains for the president following the national political conventions. Both campaigns say they expect the race to be decided by eight or nine states that do not vote consistently Republican or Democratic.

Romney was taking Saturday off from campaigning. He was trying to refocus his campaign on the economy after a difficult week dominated by foreign policy, a vulnerability.

Obama was in Washington this weekend keeping tabs on the situation in the Middle East following the deaths of a U.S. ambassador and three other Americans. While he, too, had no plans to campaign this weekend, he also was keeping his eye on winning a second term.

The ad is an expensive and expansive effort by Obama to gain the upper hand on the economy, Romney's strength, at a time when voters are reporting feeling slightly more optimistic that the president's policies are helping.

Polls in several of the most contested states show the president with a slight edge. Also, a new national survey by The New York Times and CBS News finds that Romney has lost his longstanding edge on the question of who voters view as most likely to restore the economy and create jobs. Despite that, the poll found the race narrowly divided.

Obama's new ad features snippets from both his and Clinton's convention speeches and serves as a rebuttal to Romney's argument that the nation is not better off than it was four years ago. It highlights news reports from September 2008 that describe the "worst financial collapse since the Great Depression" and says that, since then, the country has seen 30 months of private-sector job growth resulting in 4.6 million new jobs.

It argues that Obama would ask "millionaires to pay a little more" -- it doesn't mention that would come through a tax increase -- while Romney wants "a new $250,000 tax break for multimillionaires."

"We're not there yet, but the real question is, whose plan is better for you?" the ad asks.

Expect to hear the same argument next week as Obama holds rallies in Ohio on Monday, a fundraiser in New York on Tuesday and a two-city Florida swing on Thursday. The president is also expected to campaign next weekend in Wisconsin, the home state of Republican vice-presidential nominee Paul Ryan and one that Romney is working to turn competitive.

A high-ranking national security aide travels with Obama on all of his campaign trips, and officials said he would continue to be briefed on events in the Middle East and elsewhere in the world while on the road.

Romney is set to campaign in Colorado on Sunday before Monday appearances in California and Texas. He'll spend Wednesday and Thursday campaigning in Florida.

Both candidates will appear separately at a forum this week hosted by the influential Hispanic television outlet Univision.

Romney aides acknowledge they're hoping for a shift away from foreign policy, which is not the longtime businessman's strength. While Romney tried to use the week's events to question Obama's global leadership, he drew criticism from Democrats and some Republicans for his initial response to violence in Libya.

The Republican ticket is trying to hit Obama on his strength, as polling shows that Americans are more likely to trust the president who ended the war in Iraq and led the killing of Osama bin Laden on foreign policy matters.

But Romney has struggled to make the case against the sitting commander in chief as the unrest has spread. Since an initial statement mischaracterized the chaotic events, Romney has taken a mournful tone about the loss of life and instead is making a broader argument that Obama has a pattern of sending the wrong message to the world.

Anti-American protests have spread to around 20 countries, with the most violent in the Mideast. Some foreign policy experts -- particularly conservatives and former Bush administration officials -- have questioned whether Washington acted unwisely by backing Arab Spring protests that ousted autocratic leaders like former Egyptian President Hosni Mubarak, who had been traditional U.S. allies.

White House spokesman Jay Carney said the administration remained committed to Arab citizens seeking democratic reforms.

The four Americans were killed during a raid on the consulate in Benghazi, Libya, that came on Tuesday's 11th anniversary of the Sept. 11 terrorist attacks as Arabs were angered over an obscure anti-Muslim film produced by a California filmmaker.