When U.S. officials were trying to gain access to a key Al Qaeda (search) operative detained in Yemen, Vice President Dick Cheney (search) picked up the phone and called Saudi Arabia's crown prince.

The U.S. ally intervened with the Yemeni president, and the suspect was quickly sent to a friendly third country where U.S. intelligence could question him.

U.S. and Saudi officials, in rare interviews discussing joint intelligence operations, have told The Associated Press that Saudi Arabia (search) has secretly provided the United States with several diplomatic and intelligence favors in the war on terrorism.

The contributions, they said, have gone unacknowledged in part because of concerns that public disclosure might alienate a Saudi citizenry wary of cooperation with America or affect diplomatic relations with other Middle East countries.

The confirmation of more than a half-dozen acts of assistance by the Saudis comes at a time when the longtime U.S. ally is trying to counter criticism that it was soft on terrorism before Sept. 11, 2001.

Officials said the Saudi desire to counter that criticism, along with a heightened alert inside the kingdom after May 12 terrorist bombings in Riyadh (search) killed 35 people, have freed both sides to discuss previously secret cooperative efforts.

"Since Sept. 11, 2001, the two countries have exchanged more than 3,500 memorandums dealing with counterterrorism efforts," said Adel al-Jubeir, the crown prince's foreign affairs adviser. "This represents more than six memos per day and is a clear example of the intensive cooperation."

Both sides say intelligence sharing has been imperfect but is improving.

U.S. officials and congressional leaders say the flow of Saudi information at times has been halting or incomplete, especially when it comes to questions about the kingdom's own citizens. And they say Saudi attention before Sept. 11 to possible terrorist uses of Saudi-based charities was lacking.

"While the Saudi government insists that it is cooperating fully with U.S. law enforcement efforts, our officials note the cooperation has been uneven," Senate Governmental Affairs Committee chairwoman Susan M. Collins, R-Maine, said. Her committee is investigating possible terror financing schemes.

The Saudis counter they initiated the first joint terrorism task force with U.S. intelligence as early as 1997 and say they were, at times, bewildered to receive duplicative requests from multiple U.S. agencies, all unaware that another federal agency already had the information.

"Everyone is smarter after 9-11. Everyone missed the mark prior to 9-11. No one country can be blamed," said Prince Bandar, the longtime Saudi ambassador to Washington.

Both sides agree the process has improved -- particularly with the formation of joint terrorist task forces that have centralized the exchange of time-sensitive intelligence.

The Saudis say that shortly after convicted shoe bomb terrorist Richard Reid was foiled in an attack on a trans-Atlantic flight to Boston in December 2001, Saudi intelligence passed on to the CIA information from several Al Qaeda prisoners in Saudi custody.

Saudi and U.S. officials said the prisoners related they had been with Reid in Al Qaeda training camps and remembered him as having a bad temper. The prisoners even related how Reid could be calmed with ice cream, Saudi officials said.

Saudi and U.S. officials said they worked closely together to disrupt an Al Qaeda cell run by a Sudanese who plotted to use shoulder-launched missiles to shoot down a U.S. airplane taking off from Prince Sultan Air Base inside the kingdom.

Saudi officials say one of their most significant contributions has been with Yemen, a country that is a hotbed of Al Qaeda activity but which historically has had a cool relationship with the United States. U.S. officials say Yemen has made strides in recent months with its anti-terror cooperation.

Cheney's office called Saudi officials in early 2002 seeking help on the Yemeni extradition of an Al Qaeda operative named Abu Mu'az al-Jeddawi. Al-Jeddawi was running a cell believed to be plotting attacks, the officials said, and was mentioned in an FBI terrorism alert Feb. 11, 2002, that warned of possible imminent terror attacks inside Yemen or the United States.

The vice president spoke directly to Saudi Crown Prince Abdullah, and the Saudis contacted the Yemeni president to broker a deal to have al-Jeddawi extradited to Jordan, where U.S. authorities could interrogate him, according to Saudi and U.S. officials.

To help the transfer, the Saudis simply waived their right to have him extradited to their kingdom, clearing the way for his release to Jordan instead.

The Saudis got back to the vice president's office within 10 minutes of his call to report the deal was done, the officials said.

One of the most tantalizing but disputed Saudi claims of assistance occurred before Sept. 11.

Saudi Arabia's former intelligence chief said in an AP interview his government determined in late 1999 or early 2000 that eventual Sept. 11 hijackers Khalid al-Mihdhar and Nawaf al-Hazmi were Al Qaeda terrorists being sought in two terror plots.

Prince Turki al Faisal alleges his intelligence agency told the CIA in late 1999 and early 2000 that the kingdom had placed both men on its own terror watch list after learning from Al Qaeda prisoners and intelligence intercepts that al-Mihdhar and al-Hazmi might be connected to 1998 Al Qaeda attacks on U.S. embassies in Africa and a 1997 effort to smuggle weapons.

"What we told them was these people were on our watch list from previous activities of Al Qaeda, in both the embassy bombings and attempts to smuggle arms into the kingdom in 1997," Turki said.

CIA officials deny receiving such information until after the suicide hijackings occurred.

"There is not a shred of evidence that Saudi intelligence provided CIA any information about al-Mihdhar and al-Hazmi prior to Sept. 11 as they have described," spokesman Bill Harlow said. "There have been exhaustive examinations of our records, not only by us, but by congressional inquiries and no such records have surfaced. We have found information similar to that which you cite which the Saudis passed to us a month after Sept. 11."

U.S. and Saudi officials confirm the Saudis created a terror task force as early as 1997 to exchange information with the United States. They usually met once a month either in Riyadh or Washington.