Washington ? The top intelligence official at the Homeland Security Department, worried about an increased risk of attack in coming months, says al-Qaida wants to strike on U.S. soil with something other than a conventional explosive — perhaps with a chemical or biological weapon.

Retired Lt. Gen. Patrick Hughes said in an Associated Press interview Monday evening that America has gotten better at predicting and safeguarding itself against attacks since Sept. 11, 2001. But Hughes said he feared that new terrorists “are being made every single day on the streets of the Middle East.”

Hughes and his deputies at the agency’s information analysis division say the nation’s security has improved since the terrorist attacks claimed nearly 3,000 lives.

Still, significant threats remain, especially now, as high “background noise” from terrorists and heightened sensitivity during the election year have officials on guard for a possible attack.

Hughes marks the orange alert at the holidays as the start of a new era of threats. “We have a new norm,” said Hughes, who believes terrorists learned about security checks and changes implemented during that alert and have adapted.

Now — based on captured material, interviews and other sources of information — Hughes said he believed al-Qaida wants to strike with something other than a conventional explosive device. He worries about chemical and biological attacks, including a dirty bomb. And, in particular, he points to the possibility of another anthrax biological attack, following the one that wreaked havoc on the postal system, closed a Senate building for three months and killed five people in 2001.

U.S. officials are adapting, too. Unlike before the attacks, encrypted networks now link hundreds of law enforcement and security officials across the country to an operations center at the department’s campus, about six miles from the White House. When threat information indicates a heightened risk, a 24-hour operations center opens there, run out of a windowless conference room. And, bulletins to state and local officials routinely go out to inform about threats.

In late April, in one example, Homeland officials and the FBI put out a lengthy warning advising local law enforcement authorities to be on guard for possible truck bombs.

Hughes ticks off a list of terrorist attacks that began in the 1990s — Khobar Towers in Saudi Arabia, the African embassy bombings, the USS Cole attack in Yemen, bombings in Saudi Arabia and the Middle East and 9-11 — and worries that terrorists are able to show much patience.

“If the past is indeed prologue, then we are going to screw up, or they are going to get lucky,” Hughes said. “I can’t sleep.”