Washington ? The Bush administration lowered the national terror alert Thursday from orange to yellow, suggesting the immediate threat of an attack on U.S. soil had eased. Still, Americans were warned to “continue to be defiant and alert.”

Counterterrorism officials said al-Qaida remained capable of attacking, and they cautioned people not to think the threat had passed.

“Al-Qaida will wait until it believes Americans are less vigilant and less prepared before it will strike again,” Atty. Gen. John Ashcroft and Homeland Security Secretary Tom Ridge said in a joint statement.

The conclusion of the Muslim hajj holiday period played a role in the decision to lower the threat level from orange, the second-highest level on the five-part scale, Ashcroft and Ridge said. Counterterrorism officials had noted intelligence information pointing toward a possible attack around the time of the holiday, which is in early and mid-February.

Other intelligence suggested that the threat of imminent attack has abated to a degree, officials said.

The two Cabinet secretaries said lowering the alert status was “only an indication that some of the extra protective measures enacted by government and the private sector may be reduced at this time.”

A yellow, or elevated, alert is the third-highest alert on a five-step scale. It means intelligence suggests a significant risk of terrorist attacks. The orange alert is a step higher and means there is a high risk of an attack. The highest alert level, never activated since the system was instituted last year, is red.

The level was raised to orange on Feb. 7, prompting the government and businesses to impose extra security measures.