High-ranking Iraqi prisoners are uniformly denying Saddam Hussein's government had any weapons of mass destruction before the war, U.S. officials familiar with their interrogations said Tuesday.

The officials said they believe many of the prisoners are lying to protect themselves.

Still, the denials are hampering U.S. forces' search for evidence of alleged chemical, biological and nuclear weapons programs in Iraq, as the prisoners are not providing locations or other details interrogators are seeking.

By denying Iraq (search) had weapons, the prisoners may be trying to distance themselves from Saddam's rule, one official said.

American officials stand by their belief that Iraq possessed prohibited weapons and the means to make more, although none have turned up since the war started on March 19.

The Bush administration has cited intelligence pointing to prohibited Iraqi weapons programs as a justification for war.

Officials now say the weapons are either well hidden or were destroyed in the run-up to the war. There is no firm evidence they were moved to other countries, they say.

Saddam's government denied having any unconventional weapons until the end, saying it had destroyed them years before.

Fears that Saddam's military would use chemical weapons on the battlefield went unrealized, and U.S. officials have not reported any evidence that his military units were equipped with those weapons.

Secretary of State Colin Powell, under questioning before the Senate Foreign Relations Committee Tuesday (search), predicted prisoners would yet help U.S. forces find the alleged weapons.

"They will be found," he said.

Former Deputy Prime Minister Tariq Aziz (search) is among the Iraqis in custody who says his government had no prohibited weapons, officials said. So is Lt. Gen. Amer al-Saadi (search), Saddam's alleged point man on chemical and biological agents.

One unidentified scientist cooperating with American interrogators has contended the government destroyed its weapons in the run-up to the war. But his information has not been verified, officials said.

Around Iraq, American forces are finding suspicious chemicals and other possible signs of weapons programs, but nothing conclusive, officials said. So far, thorough testing has not verified any of the chemicals are weapons.

Other signs include burned documents and other evidence of an attempt to destroy evidence, officials said.

After coming up empty, military officials have largely abandoned earlier methods of searching only suspected weapons sites that were noted before the war. Now, defense officials say they are primarily going where Iraqis point them.

Spurning the proposed re-entry of U.N. weapons inspectors, the Bush administration is sending 1,000 experts to join the 200 already searching in Iraq for evidence of weapons programs.

U.S. Central Command, the military authority in Iraq, has confirmed 14 of its 55 most-wanted Iraqi leaders are in custody, including Aziz, al-Saadi and several other key officials, including several alleged weapons scientists.

The latest capture, which took place on Monday, was Amer Mohammed Rashid (search), Iraq's oil minister and a top missile expert.

Another recent catch, Farouk Hijazi (search), is an alleged link between the Iraqi government and Al Qaeda. But he has denied reports that he traveled to Afghanistan in late 1998 and met with Usama bin Laden, officials familiar with his interrogation said.

Hijazi, Iraq's ambassador to Tunisia and a former senior official in Iraqi intelligence, acknowledged meeting with Al Qaeda operatives in 1994 in Sudan, but said the Iraqi government established no ties with bin Laden's network.

Alleged Iraqi ties to terrorism was another of the Bush administration's justifications for the war.

U.S. forces near Baghdad have also captured an alleged midlevel operative working for Abu Musab Zarqawi (search), a senior associate of bin Laden, a U.S. counterterrorism official said Tuesday.

The at-large Zarqawi has been linked to the death of an American diplomat in Jordan last year. He was in Baghdad for medical treatment in 2002 and represents one of the Bush administration's links between Al Qaeda and Saddam's regime.