The Bush administration on Friday dropped the federal terrorism alert level one step, to yellow, saying intelligence pointing to an imminent attack has decreased.

The higher orange alert lasted 10 days. No domestic terrorist strikes were attempted during that period.

"The intelligence community has concluded the number of indicators and warnings that led to raising the threat level have decreased, and the heightened vulnerability associated with the Memorial Day holiday has passed," said Brian Roehrkasse, spokesman for the Department of Homeland Security.

The new level, yellow, indicates an elevated risk of terrorist attack, while the old level, orange, means a high risk.

Yellow is the middle level on a five-color scale. The lowest two levels, green and blue, and the highest, red, have not been used since the system was adopted in March 2002.

The alert level was raised on May 20 after terrorists believed linked to al-Qaida struck in Saudi Arabia and Morocco. Seventy-five people were killed, including eight Americans.

Homeland Security Secretary Tom Ridge said it was feared the incidents could mark the beginning of a wave of worldwide attacks that could include U.S. targets.