The Senate Intelligence Committee (search) held its first hearing Thursday on Iraq's weapons of mass destruction, even as Democrats and Republicans remained divided about how to examine prewar intelligence on Saddam Hussein's weapons programs.

Analysts from the CIA and other agencies, speaking to senators in the closed hearing, described the information that served as the foundation for the October 2002 National Intelligence Estimate (search) on Iraq's alleged weapons programs, a U.S. intelligence official said, speaking on the condition of anonymity.

That estimate, which said Iraq had chemical and biological weapons and an active program to develop a nuclear weapon, served as part of the Bush administration's justification for war. Many of its assertions have not been validated by teams hunting for evidence in postwar Iraq.

Sen. Evan Bayh, D-Ind., said after he left the hearing that it's too early to conclude there were no such weapons.

He said he has heard "nothing that would materially alter the conclusion" that Iraq had weapons of mass destruction. But Bayh said greater emphasis could have been placed on the uncertainties inherently involved in this kind of intelligence.

Senate Democrats are pushing for a full investigation examining whether intelligence was inaccurate or manipulated to help the Bush administration make the case for war. Republicans say an investigation would wrongly suggest misconduct and that the committee's regular oversight process is adequate for conducting a review.

Committee members were unable to resolve their differences during a closed-door meeting Wednesday. Sen. Jay Rockefeller of West Virginia, the top Democrat on the Senate panel, said talks were continuing, "but we have not made anywhere near sufficient progress."

After Thursday's hearing, Rockefeller said he considers it part of an investigation, regardless of what his colleagues call it.

Sen. Pat Roberts, R-Kan., the committee's chairman, has characterized the hearing as part of the normal course of the committee's business.

Meanwhile, closed hearings on Iraq's weapons continued for a second day before the House Intelligence Committee, where Democrats and Republicans agree about how to examine the intelligence that served as the basis for war.

The House hearing was focused on the current search for Iraqi weapons. On Wednesday, it heard testimony on the intelligence used to produce the October 2002 National Intelligence Estimate that provided an overview on Iraq's weapons programs.

The panel's top Democrat, Rep. Jane Harman of California, said in a statement that she wanted to use Thursday's hearing to also examine the prewar intelligence.

Among the questions she wanted addressed, she said, were: "Was the intelligence precise and accurate enough to enable U.S. military forces to search for stockpiles? Was finding and securing weapons of mass destruction or suspected WMD sites a high priority in the war plan?"

A committee member, Rep. Anna Eshoo, D-Calif., said before Thursday's hearing that she has "huge concerns about anything being stretched, interpretations being stretched, but it's still early."

"You can't predetermine outcomes," she said.

U.S. intelligence officials have provided the congressional committees with thousands of pages of documents. The documents describe the intelligence used to create the National Intelligence Estimate and to write Secretary of State Colin Powell (search)'s February speech to the United Nations.

Sen. Chuck Hagel, R-Neb., said in a speech Thursday that questions raised about the weapons intelligence "have unfortunately marred the perception of America's role in bringing an end to Saddam's regime, which is a historic opportunity and benefit for the people of Iraq and the world.

"These questions have raised doubts about America's credibility," said Hagel, a member of the Intelligence and Foreign Relations committees.

He said if the United States enlisted U.N. weapons inspectors to help verify any findings on Iraq's weapons of mass destruction, it "would significantly enhance America's credibility in the world."