The Saudis obtained information that the attack would involve explosives and a Syrian contact for financing, and that at least some of the four attackers would be British citizens, according to officials in several countries with direct access to the information.

The officials, who spoke on condition of anonymity because the information remains classified, cautioned that the current investigation has not connected any players from the July attacks to the original Saudi warning and that the information last December did not provide attackers' names, a date, specific location or time of attack.


But they said the information gleaned from the suspect after he was captured returning to the kingdom was detailed enough to heighten British concerns about the possibility of an attack around July in crowded sections of London, including in nightclubs, one U.S. official said. It added to numerous other pieces of intelligence flowing into Western governments that pointed to such threats, the officials told The Associated Press.

The British government said it does not comment on specific intelligence, but "takes all reports of alleged or possible terrorist threats or activity extremely seriously, and all reports are thoroughly investigated."

The British government also said its relationship with Saudi intelligence agencies is growing.
"The U.K. and Saudi Arabia continue to strengthen their already excellent counterterrorism
bilateral cooperation. But for obvious security reasons, we do not go into any detail," the
British Embassy in Washington said in a statement to AP.
On July 7, four suicide bombers killed 52 people and wounded hundreds in an attack on London's
transit network. It was the first reported suicide bombing in Western Europe. Two weeks later,
a similar attack in London failed when explosives carried by the attackers didn't go off.

Both attacks are believed to have involved young British Muslim men who were carrying bulky bags or backpacks laden with powerful, homemade explosives. Their explosive, HMDT, can be made using ordinary ingredients such as hydrogen peroxide (hair bleach), citric acid (a common food preservative) and heat tablets (sometimes used by the military for cooking).

Three of the four alleged July 7 bombers were of Pakistani descent. No one is in custody in the July 7 attack, but all of the main suspects in the July 21 plot have been charged.

After the attacks, Prince Turki al-Faisal, the Saudi ambassador in London who soon is moving to a similar job in Washington, said his government had warned the British government months earlier that it had obtained information in Saudi Arabia about a possible attack in London.

The officials said the information the Saudis provided between December and February came from a young Saudi man who was captured after using a false passport as he arrived back in the kingdom in mid-December.

The man had traveled from Iraq to Iran to the United Arab Emirates and then tried to return to the Saudi kingdom. He was using the passport of a Saudi killed in Iraq months earlier, the officials said.

The Saudi man told Saudi intelligence that he was collecting money throughout the Gulf region for a terrorist operation to be carried out in about six months in London, they said.

The man told his interrogators that the attack would involve plastic explosives purchased from Chechen rebels from the Russian mob, and be carried out by several men in a crowded location in London, the officials said.

The man told Saudi interrogators that a Libyan businessman in London was supposed to act as a facilitator for the attack, arranging lodging and cars for the operation. And he claimed one or more of the attackers were to be British citizens, officials said.

The man told his interrogators that when he was finished collecting money in the Gulf region for the operation, he was to call a specific telephone number in Syria to find out what to do with the cash, officials said.

By February, Saudi authorities had extracted additional information from the suspect that was passed to U.S. and British officials. Most of it involved descriptions, such as physical characteristics of the possible attackers, officials said.

British officials have said little about their investigations into the July 7 and July 21 terrorist attacks, and nothing has emerged about the possibility that Libyans or Syrians might have been involved in financing or planning them.

Roger Cressey, a former top anti-terrorism official in the Clinton and Bush administrations, said the Saudi report illustrates one challenge that friendly intelligence agencies face in unraveling specific terror plots - difficulty getting the names of sleeper cell members.

"You can receive information about the broad outline of a specific plot and not have enough granularity to the information that allows for the type of follow up that law enforcement can do," Cressey said.

He said terror groups carefully compartmentalize information so that a fund-raiser like the one the Saudis apparently captured "knows enough to get his job down but not enough so that if he is captured he can reveal the whole plot."

Al-Faisal, who is a former Saudi intelligence chief, has repeatedly urged Britain to crack down on two Saudi dissidents who are based in London and whom the Saudis accuse of being Islamic extremists linked to Al-Qaida.

Last week, Prime Minister Tony Blair's government announced new anti-terrorism measures that would empower it to deport or bar entry to extremist Muslims.