U.S. law enforcement officials on Friday praised Saudi Arabia's investigation into the deadly car bombings as an adviser to Crown Prince Abdullah (search) said both countries are "in the crosshairs" of the Al Qaeda terrorist organization.

An FBI (search) assessment team has visited the bombing sites and is satisfied with the Saudi efforts to secure the crime scenes and recover and preserve evidence, said a senior law enforcement official speaking on condition of anonymity.

FBI Director Robert Mueller (search) told reporters the initial Saudi probe of the blasts has been "thorough and expeditious," adding that the FBI's role will be to assist and not take over the investigation.

"We are there to help them," Mueller said at a Justice Department news conference. Attorney General John Ashcroft, appearing with him, said additional FBI agents will be sent to Riyadh in the near future to augment an initial assessment team.

Law enforcement officials say the FBI needs far better access to witnesses and evidence in the Saudi Arabia terror bombings than they got after the 1996 attack on the Khobar Towers (search) dormitory.

U.S. officials also have received an unconfirmed report that a possible terrorist attack may occur in the western Saudi city of Jiddah. The State Department said it could not confirm the credibility of the threat.

Adel al-Jubeir, foreign policy adviser to the crown prince, told reporters Friday the Saudi government will undertake its own unilateral efforts to bring down Al Qaeda (search) and will share information with U.S. investigators "almost in real time."

"We're both in the crosshairs of this organization," al-Jubeir said. "We have never had as close, or as strong, a cooperative effort between our two countries as we have now. Have we failed? Yes. On Monday, we failed. We will learn from this mistake, we will ensure it never happens again."

Authorities in both countries insist that cooperation will be better as the FBI team begins assessing how many agents and forensic experts will be needed for a full-scale investigation. It may be next week before additional FBI teams are summoned to Riyadh, as U.S. authorities seek to tread lightly on Saudi soil.

Weldon Kennedy, who retired as FBI deputy director in 1997, said the Saudis refused to let FBI agents interview suspects arrested in the Khobar truck bombing that killed 19 U.S. soldiers. Those suspects were summarily beheaded, ending a U.S. chance at gaining valuable intelligence or even proving they were actually guilty.

"They don't have a particularly good track record to really cooperating," Kennedy said. "They don't really follow through. They give lip service to cooperation."

The pace of the bombing investigation could be affected by a diplomatic dispute over precisely what security enhancements the United States sought for the housing compounds that were bombed when it became apparent a terrorist attack was imminent.

The State Department says it asked for better security at all compounds housing Westerners. The Saudis insist the request was made for only a single compound.

Whatever the case, law enforcement officials are growing increasingly concerned about lost opportunities to gather evidence and interview witnesses as the days go by.

"On any major investigation, the best time for a breakthrough on any kind of information is the first week to 10 days," said Dale Watson, who retired as FBI counterterrorism chief in October 2002. "You often get a break up front."

Sometimes just getting access to bits of evidence is the key. In the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland, a thumbnail-sized piece of circuit board from a radio used to trigger the bomb helped lead investigators to the men who purchased the radio and built the device. A Libyan intelligence agent was convicted in that case.

Assuming the Saudis give permission, the FBI is likely next to send in a "rapid deployment team" of about two dozen people that includes crime scene experts, bomb technicians, fingerprint and explosives analysts and other investigators. Ultimately, the total FBI presence could be in the hundreds, as it was for the investigation into the October 2000 bombing of the USS Cole in Yemen.

Kenya is the latest potential terrorist attack site on the State Department's radar screen. A travel warning issued Wednesday night said terrorists may target civil aviation with shoulder-fired missiles.