Washington ? President Bush’s top counterterrorism adviser warned seven days before the Sept. 11, 2001, terrorism attacks that hundreds of people could die in a strike by the al-Qaida network and that the administration was not doing enough to combat the threat, the commission investigating the attacks disclosed Wednesday.

Richard Clarke, who served as a senior White House counterterrorism official under three successive presidents, wrote to national security adviser Condoleezza Rice on Sept. 4, 2001, urging “policymakers to imagine a day after a terrorist attack, with hundreds of Americans dead at home and abroad, and ask themselves what they could have done earlier,” according to a summary of the letter included in a commission staff report. Clarke also cites the same plea in his new book.

Clarke told the commission in testimony Wednesday that while the Clinton administration treated terrorism as its highest priority, the Bush administration did not consider it to be an urgent issue before the attacks.

“I believe the Bush administration in the first eight months considered terrorism an important issue but not an urgent issue,” Clarke told the 10-member panel. “There was a process under way to address al-Qaida. But although I continued to say it was an urgent problem, I don’t think it was ever treated that way.”

Clarke’s appearance before the panel climaxed days of furor over claims in his book that the Bush administration did not do enough to pursue al-Qaida prior to Sept. 11, 2001, and has neglected the war on terrorism since then because of an obsession with waging war on Iraq.

The second day of this week’s commission hearings also produced new revelations about events prior to the attacks, including a denial of the White House’s long-standing claim that President Bush requested a briefing on the domestic threat posed by al-Qaida in August 2001.

‘We failed’

But perhaps the day’s most dramatic moment came at the start of Clarke’s testimony, when he issued an apology that prompted sobs and cheers from the front rows of the packed hearing room, which were filled with relatives of victims of the terror attacks.

“To the loved ones of the victims of 9-11, to them who are here in the room, to those who are watching on television, your government failed you,” he said. “Those entrusted with protecting you failed you. And I failed you. We tried hard, but that doesn’t matter, because we failed. And for that failure, I would ask, once all the facts are out, for your understanding and for your forgiveness.”

Administration officials inside and outside the commission’s meeting room continued to wage fierce attacks Wednesday on Clarke’s motives and credibility. The White House authorized identifying Clarke as the official who anonymously gave a background briefing for reporters in 2002 that included positive comments about Bush’s antiterrorism strategies.

Rice, who has refused to testify publicly before the commission, met with reporters late Wednesday and said that Clarke had sharply changed his view of the administration’s war on terror. “This story has so many twists and turns, he needs to get his story straight,” Rice said.

She said Clarke never raised concerns with her about the impact of the invasion of Iraq on counter-terror efforts. Rice also characterized Clarke’s Sept. 4 letter predicting deaths from a terror strike as a policy document that contained no specific warnings.

The White House released an e-mail from Clarke to Rice sent four days after the attacks that said the White House had warned law enforcement agencies and the Federal Aviation Administration that top counterterrorism officials feared a major al-Qaida attack “was coming and it could be in the US … and did ask that special measures be taken.”

Other findings

The Clarke controversy overshadowed key findings by the commission’s staff, including the fact that the hunt for Osama bin Laden and al-Qaida leaders was hampered by confusion between the CIA and the Clinton White House over rules of engagement. Though White House officials said it was clear President Clinton had provided authority for CIA operatives to kill bin Laden, the CIA believed it was required to capture him. “Working-level CIA officers said they were frustrated by what they saw as the policy restraints of having to instruct their assets to mount a capture operation,” the report says.

Sandy Berger, Clinton’s national security adviser, said the White House never was apprised of the CIA concerns and would have granted any additional authorization needed if asked. “There could not have been any doubt about what President Clinton’s intent was after he fired 60 Tomahawk cruise missiles at bin Laden in August ’98,” he said. ” I assure you they were not delivering an arrest warrant. The intent was to kill bin Laden.”

Allegations confirmed

The two staff reports issued Wednesday appeared to confirm many of Clarke’s key allegations and criticisms.

In his testimony Clarke described the Sept. 4, 2001, National Security Presidential Directive, a strategy for addressing al-Qaida that administration officials have characterized as a bold departure from the Clinton years. But Clarke said the three-stage plan differed little from strategies already in place under Clinton that included first warning the Taliban government in Afghanistan, then pressuring it to turn over bin Laden and finally ousting it through third parties.

It was only after the Sept. 11, 2001, attack that the introduction of American forces was added, though contingent plans by both CIA and the Pentagon existed, Clarke said.

Clarke also said that he had wanted the directive to say “that our goal should be to eliminate al-Qaida,” but that Bush officials called that “overly ambitious.” It was reworded to say the goal was to “significantly erode” bin Laden’s network. After the Sept. 11 attacks, the word “eliminate” was added back into the directive, Clarke said.

Jamie Gorelick, a Democratic commission member and former deputy attorney general, asked Clarke whether Rice’s recent statement that the Bush plan “called for military options to attack al-Qaida and Taliban leadership, ground forces and other targets, taking the fight to the enemy where he lived” was accurate.

Clarke responded, “No, it’s not.”