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President Obama vowed, during his second inaugural address Monday, to "manage crisis abroad" in pursuit of a more "peaceful world."

But four years after the president first took the oath, the task remains perhaps his most daunting.

Moments before Obama spoke at the west front of the Capitol, confirmation that two more Americans had been killed in the hostage standoff in Algeria undercut the president's optimism. The news ups the tally of U.S. citizens killed to three, while seven others made it out safely.

The brutal, and evidently planned, attack in the Sahara underscores how much work is left to be done on the world stage as Obama embarks on his second term. While the president spent the bulk of his first four years focused inward -- on jolting the American economy, overhauling the health care system and campaigning -- the number of international challenges has only mounted.

The attack in Algeria is the latest symptom of an emerging threat outside the Afghanistan-Pakistan axis that has been the focal point of America's "war on terror" since 2001. Plots have sprung out of Yemen, out of Libya and now Algeria, representing a massive band of instability spanning North Africa and the Arabian Peninsula -- not to mention the convulsing civil war in Syria.

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Despite the challenge ahead, Obama on Monday sustained the message of reconciliation that drove his first term's foreign policy.

Check out FoxNews.com's full Inauguration 2013 coverage

"We will defend our people and uphold our values through strength of arms and rule of law," Obama said. "We will show the courage to try and resolve our differences with other nations peacefully -- not because we are naïve about the dangers we face, but because engagement can more durably lift suspicion and fear."

When Obama was first elected four years ago he talked an ambitious foreign policy. His first-term agenda included restoring America's tattered international image, ending two wars, using a carrot-and-stick approach to Iran's nuclear program and helping broker peace in the Middle East. Fast forward four years and the harsh reality is that many goals are unmet.

His biggest accomplishment, and the one that factored most into his reelection campaign, was the take-down of Usama bin Laden in Pakistan. But Al Qaeda's affiliates and allies have continued to threaten U.S. interests abroad, with a former Al Qaeda operative claiming credit for the attack in Algeria, where a total of 38 hostages reportedly have died.

Militants also stormed the U.S. diplomatic compound in Benghazi in September, killing four Americans. The attackers have not yet been brought to justice.

As the president starts his second term, he will be forced to confront a number of other still-pending policy issues that could affect America's dominance in the global arena -- but it won't be easy.

During his first term, Obama signaled a willingness to work diplomatically with Tehran over nuclear capabilities. When that didn't work, the U.S. tried coming down harder, threatening economic sanctions. In the months ahead, U.S. officials will try once more -- this time, talking directly with Iranian officials. It's important the meeting goes well. Obama has repeatedly said that it is "unacceptable" for Iran to have access to nuclear-weapon capabilities. If Iran doesn't back down, Obama will likely face more questions on whether the U.S. would back up its words with military action -- or let Israel do so.

The scene isn't much better in the Middle East.

Two days before the president's first inauguration in 2009, Hamas and Israel had agreed to a cease fire after a three-week war. Today, little if anything has been resolved. Getting beyond the centuries-old political divide has proven tough for the Obama administration. Last week, Israel's Prime Minister Benjamin Netanyahu dismissed Obama's reported displeasure with his hard-line policies toward the Palestinians, some say paving the way for a clash in the future.

In Syria, the Obama administration has steered clear of military involvement but President Bashar al-Assad's crackdown which has left 60,000 dead could force the United States' hand. Concerns that the Assad government may use chemical weapons have continued to plague the country. If those allegations are proven true, it may mean the U.S. could get militarily involved.

On Monday, Arab League Chief Nabil Elaraby said resolving Syria's crisis had not produced "a flicker of hope."  Elaraby called for the U.N. Security Council to adopt a resolution calling for a cease-fire in Syria. He also wants to create a monitoring force to make sure the job gets done.

In China, the White House's big plan to build an economic partnership hit a wall when accusations that the U.S. was trying to curb China's ambitions surfaced.

Still, some say that while big problems in Iran persist and Israeli-Palestinian tensions continue to escalate, it's the smaller conflicts and threats in Algeria, Mali and Libya that serve as a fresh reminder of the president's uphill battle ahead.

On Sunday, the chairman of the House Intelligence Committee said that several reports had surfaced that "something big" was about to happen against a Western target but that there were few details that accompanied the threat.

"We didn't know for sure, for certain it would be this particular place under those circumstances, but we knew that they were trying to find a Western target, which this clearly was," Rep. Mike Rogers, R-Mich., said on ABC News' "This Week."

Roger's comments came after the four-day hostage crisis ended in Algeria. There have been three arrests so far. On Sunday, a video surfaced of terrorist leader Mokhtar Belmokhtar claiming responsibility for the attack.