U.S. forces intensified their hunt for Saddam Hussein near his hometown of Tikrit on Wednesday as Secretary of State Colin Powell called Iraq's former leader "a piece of trash waiting to be collected. "Saddam is no longer bad news," Powell told Reuters. "The noose is tightening, but I can't speculate on how close one might be to actually capturing Saddam."

President Bush, in a Rose Garden press conference, also said he did not know how close U.S. forces were to finding Saddam, who was ousted April 9. But Bush insisted progress was being made.

"If you had asked me right before we got his sons how close we were to get his sons, I'd say, 'I don't know, but we're on the hunt.' And we're making progress," Bush said. U.S. forces killed Saddam's two eldest sons, Uday and Qusay, on July 22 in the Iraqi city of Mosul.

Task Force 20, a special operations team hunting members of the former regime, and the Army's 4th Infantry Division, have conducted 51 raids in Iraq and detained 559 suspected Saddam loyalists since Tuesday, U.S. Central Command said.

U.S. forces are searching with satellites that record suspicious changes on the Iraqi terrain, spy aircraft that scour hiding spots with thermal scans and unmanned drones that feed live video to military headquarters in Iraq, said Lt. Col. Ted Martin, the 4th Infantry Division's operations officer.

Martin said U.S. forces also are using high-tech tricks. The radar in Apache helicopters, originally designed to target moving tanks, has been reconfigured to track cars and detect unusual traffic patterns.

"The systems, the people and the training we have here aren't designed to hunt one human being," Martin said. "But everything we have can be applied to tracking down this key leader."

When the Army receives a report of a suspicious meeting, it will deploy unmanned planes and send in helicopters, Martin said. If the lead looks promising, infantry troops backed by Bradley fighting vehicles can be dispatched.

He said the Army also has generated images of what Saddam could look like after nearly four months on the run. Some of the images show him with a beard, but without his trademark mustache.

U.S. forces also are relying on tips from Iraqis. Since the deaths of Uday and Qusay last week, the U.S. military reports a surge in the number of tips. The information indicates that Saddam may be hiding in old bunkers and the homes of friends and relatives.

"I don't think it's going to be a satellite that catches Saddam Hussein," Martin said. "I think it's going to be a soldier with a rifle."

Also Wednesday, a CIA official said his agency's analysis of an audiotape aired this week purporting to be Saddam was almost certainly authentic. On the tape, Saddam said his sons died as martyrs and U.S. forces would be defeated.