Here’s your cheerful five-year forecast from the Department of Homeland Security.

WASHINGTON — The terrorism threat to the United States over the next five years will be driven by instability in the Middle East and Africa, persistent challenges to border security and increasing Internet savvy, says a new intelligence assessment obtained by The Associated Press.

Chemical, biological, radiological and nuclear attacks are considered the most dangerous threats that could be carried out against the United States. But those threats are also the most unlikely because it is so difficult for al-Qaeda and similar groups to acquire the materials needed to carry out such plots, according to the internal Homeland Security Threat Assessment for the years 2008-13.

The al-Qaeda terrorist network continues to focus on U.S. attack targets vulnerable to massive economic losses, casualties and political “turmoil,” the assessment said.

On Dec. 3, Homeland Security Secretary Michael Chertoff said the threat posed by weapons of mass destruction remains “the highest priority at the federal level.” Chertoff told reporters that more people, such as terrorists, will learn how to make dirty bombs, biological and chemical weapons. “The other side is going to continue to learn more about doing things,” he said.

The report, marked “For Official Use Only,” does not specify its audience, but the assessments typically go to law enforcement, intelligence officials and the private sector. When determining threats, intelligence officials consider loss of life, and economic and psychological consequences.

Intelligence officials also predict that in the next five years, terrorists will attempt a destructive biological attack. Officials are concerned about the possibility of thousands of U.S. citizens being infected, overwhelming regional health care systems.