As the 10th anniversary of the Sept. 11 attacks approach, the United States has been emphasizing caution in case security problems arise.

U.S. Defense Secretary Leon Panetta authorized raising the force-protection level for military installations, Pentagon Press Secretary George Little said in a news release Wednesday. This follows a worldwide travel warning put out by the U.S. State Department on Saturday, where they claim that al Qaeda is still capable of carrying out attacks on American citizens.

The heightened security alerts follow a move by the Department of Homeland Security warning Americans to remain vigilant as the anniversary approaches.

As we approach the tenth anniversary of the September 11, 2001 terrorist attacks, the safety and security of the American public remains our highest priority, Napolitano said in a statement released last Friday. While threats remain, our nation is stronger than it was on 9/11, more prepared to confront evolving threats, and more resilient than ever before.

Government officials have been trying to strike a balance between offering caution and stirring up unnecessary fear. There is currently no evidence that an anniversary attack was actively in the works, although evidence gained from bin Laden's compound showed that he, along with top deputy Attiyah Abd al-Rahman, were planning an additional Sept. 11 attack.

It seemed more aspirational than real, and given the pressure on the al Qaeda network, maybe not even feasible, a senior official told the New York Times , who spoke on condition of anonymity due to the sensitive nature of the intelligence. But what it did was affirm for us that, contrary to past analysis, bin Laden had put some emphasis on the anniversary.

The Times points out that with the nation in economic distress, the White House is eager to address the achievements of security that has been made, although they have been careful about using the president himself to relay that message. President Obama will join other government officials in reading a poem at Ground Zero and will lay a wreath at the Pentagon.

But other advisers are speaking out more. Notably, counterterrorism adviser John Brennan is speaking about counterterrorism policy at events throughout Washington this week, and Panetta has been visiting 9/11 sites recently.