The Sept. 11 attacks in New York and Washington could have been orchestrated by a small group of men in England, Germany and the United Arab Emirates, according to sources familiar with the U.S. investigation.

"One should not focus on one individual, but focus one's attention on a series of networks across the world," FBI director Robert Mueller said Friday.

At least one of those men suspected in the planning--an Algerian pilot located in London--is already in custody. Officials are seeking another man in the United Arab Emirates who was sent a package by Mohamed Atta, the suspected leader of the hijacking teams, a few days before Atta allegedly flew one of the hijacked planes that struck the World Trade Center.

In the U.S., several individuals suspected of crimes possibly related to the attacks were arrested on Friday.

Yousseff Hmimssa, charged with visa fraud, was captured in Iowa. Hmimssa's alias, Michael Saisa, appeared on documents seized in a Sept. 17 raid in Detroit, according to court records. Two other men charged with the same crime--Ahmed Hannan and Karim Koubriti--were arrested earlier in the day during a search for a man on the FBI's watch list.

Two men accused of attempting to obtain fraudulent truck driving licenses were arrested in Pennsylvania. In addition, the FBI was investigating a report that three Arab men visited a Lake Worth, Fla. truck driving school on the afternoon of Sept. 11 and tried to obtain rushed training for hauling hazardous materials.

Pilot Arrested in London

An Algerian pilot arrested in London helped train the hijackers who crashed a jetliner into the Pentagon, a British prosecutor said in court Friday.

Lotfi Raissi, 27, also took at least one of the hijackers on a flight June 23 from Las Vegas to Arizona, prosecuting attorney Arvinda Sambir said in Magistrates Court.

Raissi, who was arrested on Sept. 21, is the first overseas suspect that officials have directly linked to the terrorists who carried out the Sept. 11 attacks in New York and Washington.

"He was a lead instructor of four of the pilots that were responsible for the hijackings," Sambir said.

Sambir said that Raissi made several trips to the United States this summer, trained with several of the suspected hijackers and flew with one of them. She did not provide further details about the Nevada to Arizona flight.

Raissi started training for a U.S. commercial pilot's license in 1997, Sambir said. It was unclear where Raissi allegedly attended flight schools with the hijackers, although Sambir mentioned a flight school in Arizona. One of the pilots on American Airlines Flight 77, which crashed into the Pentagon, is believed to have attended flight school in Arizona in 1997.

Ed Hall, a spokesman for the FBI's office in Phoenix, declined to say whether Raissi and suspected hijacker Hani Hanjour were connected.

Raissi was formally arrested Friday after a week in custody when a federal court in Arizona issued an arrest warrant alleging that he gave false information on a Federal Aviation Administration form. The warrant also says Raissi failed to disclose a 1993 criminal conviction for theft in England.

He will remain in custody in London pending an additional hearing scheduled for Oct. 5. U.S. authorities have 60 days to file an extradition request, British officials said.

He has not been formally charged with any offense but Sambir said further allegations were expected. "It is no secret that conspiracy to murder is being looked at."

Richard Egan, Raissi's defense lawyer, said his client adamantly denies any involvement in the terror attacks.

Searching for Suspects Abroad

Meanwhile, photographs released in Washington of the 19 suspected hijackers were published in newspapers throughout the Arab world on Friday. U.S. officials hope wide distribution of the photographs will help in the investigation.

Since the terrorist strikes, some 20 people have been arrested in a European sweep for suspected associates of Usama bin Laden, thought to be the mastermind behind the attacks.

In Madrid, Spain, six Algerians on Friday were ordered held without bail on charges they belong to an militant Algerian group funded by bin Laden.

The suspects have not been linked to the Sept. 11 attacks but Juan Cotino of the Spanish National Police said the six had direct links with others arrested in Europe who were planning suicide attacks against U.S. targets on the continent, including the U.S. embassy in Paris.

Spanish officials picked up the six after they learned that a Tunisian arrested in Belgium with bomb-making material and documents suggesting he was planning a suicide attack had met with the Algerians in Spain.

Raissi, who lived near London's Heathrow airport, was one of four people detained by British police on Sept. 21. Two were released without charge and have been identified in news reports as Raissi's 25-year-old wife, Sonia and his 29-year-old brother, Mohamed. A fourth person identified as Abu Imard, who was arrested in Birmingham, was released Friday evening.

Raissi's relatives have told journalists that he flew jets in the United States for several years and was taking further training at Heathrow.

"Of course Lotfi has flying manuals at home — he is learning to be a pilot," Raissi's uncle, Kamal Raissi, told a reporter after his nephew's arrest.

According to a database search by The Associated Press, Raissi appeared to have lived in Arizona for several years in the late 1990s. He listed addresses in Phoenix on four pilot licenses.

Other court records show Raissi received a February 1999 traffic ticket in suburban Mesa, Ariz., that listed a north Phoenix address.

Police in central England were still holding three other men detained Tuesday under the Terrorism Act. Police said the men were linked to previous arrests in France and Belgium, but gave few details.

Scotland Yard confirmed Friday that 11 of the suspected hijackers passed through British airports this year.

Ten arrived at Gatwick or Heathrow airports on flights from Dubai between April and June, Scotland Yard said, and all caught connecting flights out of the country within three hours. An 11th suspected hijacker passed through Britain in January, police said.

Deputy Assistant Commissioner Alan Fry, head of Scotland Yard's Anti-Terrorist Branch, said the FBI has passed on 100 requests to trace suspects, witnesses and others connected to the case.

"The indications are that we can expect the number of requests from the FBI to increase over coming weeks. That does not mean there is more evidence of a major part of this conspiracy taking place in this country," Fry said.

The Associated Press contributed to this report.