The top CIA counterterrorism officer who tracked Osama bin Laden through the mountains of Afghanistan says the United States could have captured the terrorist leader if President George W. Bush and the American military had devoted the necessary resources to the hunt and capture.

In addition, says Gary Bernsten, a decorated espionage officer, the post-Cold War downturn in recruitment and attention to espionage has left a crippled spy agency that will need a decade or more to build up its clandestine service for the U.S. war on terrorism.

Berntsen led a paramilitary unit code-named "Jawbreaker" in the war that toppled the Taliban after the September 11 attacks.

He says his Jawbreaker team tracked bin Laden to Afghanistan's Tora Bora region late in 2001 and could have killed or captured the al Qaeda leader there if military officials had agreed to his request for an additional force of about 800 U.S. troops. But the administration was already gearing up for war with Iraq and troops were never sent, allowing bin Laden was able to escape.

His account contradicts public statements by Bush and former Gen. Tommy Franks, who maintained that U.S. officials were never sure bin Laden was at Tora Bora.

Berntsen says CIA Director Porter Goss faces an uphill battle to fill the agency's senior ranks with aggressive, seasoned operatives.

"He's probably more aggressive than most of the senior officers in the clandestine service. So I think he's having to pull them along a bit," Berntsen said in an interview.

"(Goss) is trying to improve the situation. But it's going to be tough. The rebuilding is going to take years. A decade, at least," he told Reuters late last week.

The CIA, widely criticized for lapses involving prewar Iraq and the September 11 attacks on New York and Washington, has seen its clandestine staff dwindle to less than 5,000 employees from a peak of over 7,000, intelligence sources say.

Experts blame a post-Cold War downturn in recruitment for a current lack of seasoned clandestine operatives that has been exacerbated by a rush to lucrative private sector jobs in recent years.

"We have a smaller number of really, really aggressive, creative members of our leadership in the senior service," said Berntsen, who recently published a book about his exploits in the war on terrorism, titled "Jawbreaker" (Crown Publishing).

Former CIA Director George Tenet told the September 11 commission in April 2004 the CIA would need five years to produce a clandestine service fully capable of tackling the terrorism threat.

Goss later said at his September 2004 Senate confirmation hearings that rebuilding the clandestine operation would be "a long build-out, a long haul."

President George W. Bush issued an order last year that called for a 50 percent increase in CIA clandestine officers and analysts to be completed "as soon as feasible."

"The CIA is moving aggressively to rebuild and enhance its capabilities across the board," CIA spokesman Paul Gimigliano said.

But intelligence sources say the rebuilding process has been complicated by disaffection for Goss' leadership within the clandestine service.

Years of double-digit growth in federal spending on intelligence that followed the September 11 attacks may also be about to end.

John Negroponte, the new U.S. director of national intelligence, has endorsed an intelligence budget for fiscal year 2007 that is relatively flat, with current spending levels believed to total about $44 billion for the 15-agency intelligence community. Fiscal 2007 begins in October.

Berntsen, 48, who also led the CIA Counterterrorism Center's response to the 1998 al Qaeda bombings of U.S. embassies in East Africa, sued the CIA in July, accusing the spy agency of trying to stop him from publishing his book.

Gimigliano said the CIA reviewed Bernsten's book before publication only to ensure that it contained no classified information.

In the book, Berntsen says his Jawbreaker team tracked bin Laden to Afghanistan's Tora Bora region late in 2001 and could have killed or captured the al Qaeda leader there if military officials had agreed to his request for an additional force of about 800 U.S. troops.

But the troops were never sent and bin Laden was able to escape, he said.

His account contradicts public statements by Bush and former Gen. Tommy Franks, who maintained that U.S. officials were never sure bin Laden was at Tora Bora.