Updated

The White House said Wednesday that the failure to capture Osama bin Laden in the seven years since the Sept. 11 attacks shows the limitations of U.S. military and intelligence power.

"This is not the movies. We don't have super powers," said White House press secretary Dana Perino. "But what we do have is very dedicated people who are working with our allies and trying to bring (al-Qaida leaders) to justice."

Bin Laden, leader of the al-Qaida network that orchestrated the deadliest terrorist attack in U.S. history, is believed to be in the lawless tribal belt of Pakistan and Afghanistan.

His status as an at-large enemy of the United States tends to come back into focus with every somber anniversary of the 2001 attacks. Beyond a matter of national security, bin Laden's elusiveness has elicited fire from President George W. Bush's critics, who accuse Bush of being wrongly focused on Iraq.

"The Bush administration has failed to put the necessary resources and manpower into the hunt for America's No. 1 enemy," Senate Majority Leader Harry Reid said Wednesday. "President Bush has rightly said that the war on terror is about more than just one man. Yet seven years after 9/11, the president has allowed that one man's vast al-Qaida network to regroup."

Perino said the intelligence community's hunt for bin Laden has been relentless, and that Bush has never let up.

She added that the government has had success in disrupting the terror network, including the capture of the confessed Sept. 11 mastermind, Khalid Sheikh Mohammed. He is jailed at the U.S. Navy base in Guantanamo Bay, Cuba as he awaits trial.

Bush and first lady Laura Bush will mark the anniversary of the Sept. 11 attacks on Thursday during a moment of silence on the South Lawn. It will happen at 8:46 a.m. — the exact moment in 2001 when terrorists slammed the first of two jetliners into the World Trade Center in New York. The president also will attend a ceremony at the Pentagon for the dedication of a memorial for the people killed there.

"Tomorrow is obviously a very sober anniversary for Americans," Perino said. "The president thinks about 9/11 every single day when he wakes up and before he goes to bed. This is what he's concerned about. He's always been concerned about another attack on our country. Thankfully, we haven't had one."