London, England (CNN) -- Counterterrorism officers were Saturday searching the suspected London home of a man at the center of an incident aboard a U.S.-bound passenger flight that Britain's home secretary described as a "potentially serious security threat."
The search, which focused on a upscale block in the heart of London's embassy district, followed the incident on Friday in which a Nigerian man ignited a small explosive device on a flight from Amsterdam to Detroit.
The incident triggered an increase in security at UK airports and at Schiphol in Amsterdam, where the suspect in the attempted attack on a Northwest flight went through "normal security procedures," according to the security officials.
In the British capital, a spokesman for University College London confirmed they had a student named Umar Farouk Abdul Mutallab enrolled in their Department of Mechanical Engineering from September 2005 to June 2008.
The name matched the identity of the suspect said by U.S. authorities to have been involved in an attempted terrorist attack.
UK Home Secretary Alan Johnson said he is following the case closely and has assured the public that police in Britain are working closely with U.S. investigators "to uncover the full background to the incident."
"We will ensure that the UK continues to have in place the most appropriate security measures to protect the public from the terrorist threat wherever it originates from," he said.
British Prime Minister Gordon Brown added in a separate statement: "The security of the public must always be our primary concern.
"We have been working closely with the U.S. authorities on investigating this incident since it happened yesterday. Because of the serious potential threat posed by the incident, I have spoken to the commissioner of the Metropolitan police, whose officers have been carrying out searched of properties in London.
"We will continue to take whatever action necessary to protect passengers on airlines and the public," Brown added.
One piece of information led police to an ornate building on Mansfield Street in London, where Abdulmutallab may have once lived in a basement apartment. It wasn't clear as to what police were searching for.
U.S. security sources told CNN that Abdulmutallab flew into Amsterdam's Schiphol Airport on a KLM flight from Lagos, Nigeria. A U.S. administration official said the suspect did not undergo secondary screening in Amsterdam, though Schiphol officials say all connecting passengers bound for the United States undergo secondary searches.
Schiphol officials said they boosted the secondary screening for U.S.-bound connecting passengers Saturday, doing body searches and bag checks instead of using the usual metal detectors and X-ray machines. The measures were being implemented at the request of U.S. authorities, a Schiphol spokesman said.
There was also increased security Saturday for U.S.-bound passengers in Britain, whether they were connecting through Britain or flying direct.
BAA, which operates several British airports including London's Heathrow, said all passengers on U.S.-bound flights will now be subject to the secondary screening at the gate. The screening used to happen on a random basis.
There were no reported delays from Heathrow Saturday, but passengers boarding a U.S.-bound Virgin Atlantic aircraft were told there would be no in-flight electronic entertainment in the wake of the incident.
Britain's Department for Transport said U.S. authorities requested the additional measures.
"Passengers traveling to the United States should expect their airline to carry out additional security checks prior to boarding," BAA said. "To support this important process, which will take time, we would advise passengers to leave more time to check in and limit the amount of baggage being taken on board the aircraft. If in any doubt, please contact the relevant airline for further information."
The British Department for Transport said it would assess the measures "as necessary" as the situation develops.
The incident in Detroit will now focus attention on the searching of connecting passengers, especially those going to the United States, CNN Correspondent Richard Quest said.
"Previously discretionary searches are now likely to be mandatory and, certainly in the near future, all U.S.-bound passengers should expect to be searched before boarding the aircraft," he said.
-- CNN's Per Nyberg and Simon Hooper in London, England, and Richard Quest and Erin McLaughlin in Amsterdam, Netherlands, contributed to this report.