The official confirmed a report in The Philadelphia Inquirer that the doctors had contacted the Educational Commission for Foreign Medical Graduates, a nonprofit organization in Philadelphia that screens foreign citizens wishing to train or work as doctors in the United States.

Nancy O’Dowd, a spokeswoman for the Federal Bureau of Investigation, said one of them “was applying” for approval to practice in the United States. “But we don’t believe he took the test,” she told The Associated Press.

The law enforcement official, who spoke on condition of anonymity because of the continuing investigation in Britain, said investigators had found no evidence that any of the eight people arrested in the case had ever been in the United States.

In London on Friday, an Iraqi doctor, Bilal Abdulla, became the first to be charged since Britain was plunged into its newest terrorism alert one week before, when the police discovered two Mercedes sedans in London packed with nails, gasoline and gas canisters. Dr. Abdulla, 27, was identified as one of the two men who drove a Jeep Cherokee into the entrance to a check-in area at Glasgow Airport and set it afire.

The second man, identified as Khalil Ahmed, was badly burned in the attack and was moved for clinical reasons from the Royal Alexandra Hospital near Glasgow to a burn unit in the city’s infirmary, medical authorities said Friday. The British authorities have said they suspect that the two men set the failed car bombs in London, then raced 400 miles back to the Glasgow area and worked frantically to carry out the airport attack before the police closed in.

Dr. Abdulla was seen in amateur television video being led away by police officers as the Jeep Cherokee went up in flames. The Crown Prosecution Service ruled that he should be charged with “conspiracy to cause explosions following incidents in London and Glasgow on 29 June 2007 and 30 June 2007.”

The charge, brought under a law dating to 1883, accused him of conspiring “with others to cause explosions of a nature likely to endanger life or cause serious injury.” It carries a maximum life sentence. The police said Dr. Abdulla would be arraigned Saturday.

The investigation widened in Australia as well, where the police this week detained Mohammed Haneef, 26, who had worked in Britain and was seeking to fly to his native India when he was arrested. On Friday, the authorities questioned and released five more Indian doctors and raided two hospitals in a search for evidence on computers, the Australian police said.

Citing federal law enforcement officials, NBC News reported Friday that Dr. Haneef was one of the two doctors who had inquired about practicing medicine in the United States. The other was Mohammed Jamil Asha, 26, a Jordanian born in Saudi Arabia, who was arrested last week in Britain.

Word that two of the doctors implicated in the British attacks had asked, however preliminarily, about working in the United States sent tremors through the American medical community, particularly among foreign-born physicians.

“I’d like to think there would not be concerns,” said Dr. Susan D. Wolfsthal, director of the internal medicine residency program at the University of Maryland School of Medicine. “But there have been times in our history when entire groups of people have been blamed for the actions of a few.”

Foreign citizens or American graduates from foreign medical schools accounted for more than 228,665 of the 902,053 practicing physicians in the United States in 2005 — just over 25 percent, according to the American Medical Association. The Congressional Research Service said their presence “in many rural communities of the United States has allowed states to ensure the availability of medical care to their residents.”

Most states require that foreign-trained doctors participate in a medical residency in the United States before they can be licensed to practice here, even if they already practiced overseas, said Stephen S. Seeling, vice president for operations of the Educational Commission for Foreign Medical Graduates.

In a typical year, the organization certifies the educational qualifications of about 11,000 foreign-trained doctors, nearly 20 percent of whom are American citizens who trained overseas. Of that number, only about 7,000 a year are able to land one of the highly competitive residency posts, Mr. Seeling said.