Washington ? Because Iraq concealed its banned weapons so well, it will take time to interview scientists and pore over seized documents to find the hiding places, say Bush administration officials who reject charges the White House overplayed prewar intelligence to justify the invasion.

Answering claims that the administration exaggerated the threat posed by Saddam Hussein, Secretary of State Colin Powell and national security adviser Condoleezza Rice expressed confidence Sunday that Iraq’s weapons of mass destruction will be found.

“I’m sure more evidence and more proof will come forward as we go down this road,” he told “Fox News Sunday.”

Powell said his prewar statement to the United Nations — that there was no doubt Saddam had the capability to produce and use such weapons — had been vetted for days by U.S. intelligence analysts.

“We spent four days and nights out at the CIA, making sure that whatever I said was supported by our intelligence holdings,” Powell said.

But weeks of searches in Iraq by military experts have not validated the administration’s portrayal of Iraq’s weapons capabilities.

Alleged stockpiles of chemical and biological weapons have not turned up, nor has significant evidence of a nuclear weapons program.

The discovery of two Iraqi truck trailers, equipped with fermenters, is the strongest evidence yet that Saddam had a biological weapons program. Still, no actual biological weapons have been found.

The lack of evidence has raised questions about whether the intelligence, which led to the war, was inaccurate or inflated.

Vice Adm. Lowell Jacoby, head of the Defense Intelligence Agency, acknowledged last week that he had no hard evidence of Iraqi chemical weapons last fall, but believed Iraq had a program to produce them. Powell said parts of the DIA report have been taken out of context.

“The sentence that has gotten all of the attention, in this two-page, unclassified summary, talked about not having the evidence of current facilities and current stockpiling,” Powell said. “The very next sentence says that it had information that weapons had been dispersed to units. Chemical weapons had been dispersed to units.”

Rice said the justification for war was grounded in information from CIA directors, intelligence reports from abroad, information from U.N. weapons inspectors and efforts by Saddam’s government to conceal what it was doing.

Rice also pointed to former President Clinton’s statement in Dec. 16, 1998, to explain missile strikes he ordered against military and security targets in Iraq. “I have no doubt today, that left unchecked, Saddam Hussein will use these terrible weapons again,” Clinton said then.

“No one ever said that we knew precisely where all of these agents were, where they were stored,” Rice told on NBC’s “Meet the Press.”