The heads of America’s intelligence agencies rolled out their annual National Threat Assessment Thursday, warning members of Congress about the increasing danger that homegrown terrorists pose to the country.

"Absolutely our No. 1 priority” is identifying Americans intent on doing harm to their own country, Michael Leiter, the director of the National Counterterrorism Center, told the House Intelligence Committee.

The panel of intelligence officials also cited the devastating potential for cyberattacks and defended the performance of US intelligence-gatherers in the Middle East, who have been widely criticized for failing to predict the current showdown on streets of Egypt.

While homegrown actors represent a “numerically small” segment of the terrorist threat, they have disproportionate access to US facilities, noted Director of National Intelligence James Clapper. He said that he remains “especially focused on Al Qaeda’s resolve to target Americans for recruitment.”

This focus is the result of the damage that US forces have done to Al Qaeda in places like Pakistan, officials argue. US success in targeting insurgent operatives has in turn encouraged Al Qaeda to look for other ways to harm America – specifically, recruiting Americans to take part in terrorist attacks on their home soil, they say.

“They are now resorting to other ways to go after this country,” said CIA Director Leon Panetta. “That’s the nature of the kind of threats that we are now dealing with.” While these potential attacks are likely to be less sophisticated, he added, Americans who might take part in them are “tougher to find.”

Mr. Leiter of the National Counterterrorism Center warned that these Americans are also increasingly linking up with each other through internet forums like Facebook. The challenge, he added, is identifying these people while still protecting US civil liberties.

60,000 malicious programs and viruses ID'ed each day

At the same time, the nation’s intelligence agencies are grappling mightily with cyberattacks, which are growing in frequency and in effectiveness. Mr. Clapper estimates that there are some 60,000 new malicious programs and viruses “identified each day.” The loss of intellectual property to cybercrime has cost businesses worldwide “approximately $1 trillion,” he added.

“The incredible loss of US intellectual property through cyberespionage is something that could sap American power not just in the long term but in the medium term,” says Kristen Lord, vice president of the Center for a New American Security, which is in the midst of conducting a year-long cybersecurity research project.

“It’s something that companies we talked to are very worried about," she said. "Often, their systems have been penetrated, and they aren’t even aware of it.”

As a result, they are lobbying American intelligence agencies to share more information about how best to defend their systems.

The problem with combating cyberattacks, however, is that perpetrators are notoriously difficult to identify, making it hard to defend against the threat, let alone retaliate. “You don’t know if it’s a state actor, a group of individuals acting at the behest of a state actor, or a group of high school kids across the street,” Federal Bureau of Investigation Director Robert Mueller explained to the committee.

This means, he added, that today there are not just intelligence officers, but electronic and cyberprobes intruding into networks and extracting information that states hostile to America “previously needed to recruit agents to obtain.”

These cyberattacks, Mr. Mueller said, have the potential of “bringing down pieces of infrastructure if not adequately protected” – including electrical grids and airlines. “One of the things we’re hearing is about the threat of foreign governments creating cyberalliances with highly capable individuals,” Ms. Lord of CNAS adds, “including cybermercenaries who may also work with terrorist organizations.”

Egypt's 'earthquake'

Even as they issued their warnings, the nation’s top intelligence officials were also called upon to defend their work in Egypt. Clapper endeavored to do that, noting that the intelligence community has long sounded the alarm on the political repression and economic hardship that contribute to instability in the Mideast.

Clapper argued, too, that events such as the uprising in Egypt are difficult to predict. The departure of an autocrat in Tunisia under mass popular pressure helped spark a movement in Egypt, he explained. “It’s hard to foretell the impact of a fruit vendor who had his fruit stolen and self-immolated … that served as a catalyst for more widespread outbreak” in Tunisia and, later, Egypt, Clapper noted.

That said, Mr. Panetta conceded that the CIA, for its part, needs “to do a better job evaluating the triggers” that can spark such events, including “the large numbers of youth and the whole role of the internet” that allows activists to quickly organize demonstrations. Panetta added that he has put together a 35-member task force to focus on “better collection on issues like popular sentiments” and “the strength of the opposition.”

In the agency’s defense, however, he offered an analogy, comparing such intelligence collecting to predicting an earthquake. “People can tell you where the tremors are, where the fault lines are – they can even tell you that the threat of something happening is close,” Panetta said. “But they can’t tell you when the earthquake is going to take place.”