Source: US knew of terror suspect

An official briefed on the attack on a Detroit airliner says the US has known for at least two years that the suspect in the attack could have terrorist ties.

The official tells the Associated Press that the Nigerian suspect, Umar Farouk Abdul Mutallab, has been on a list that includes people with known or suspected contact or ties to a terrorist or terrorist organization.

The official spoke on condition of anonymity because the investigation is ongoing. The list is maintained by the US National Counterterrorism Center. It includes about 550,000 names. People on the Terrorist Identities Datamart Environment list are not necessarily on the no-fly list. New York congressman Peter King says Mutallab was not on the no-fly list.

Meanwhile, British police searched a London apartment Saturday as authorities probed Mutallab's background. A prestigious London university said Saturday that a man with a similar name had studied mechanical engineering at the school for three years.

University College London said a man called Umar Farouk Abdul Mutallab was enrolled at the school from September 2005 to June 2008. In Nigeria, the father of Umar Farouk Abdul Mutallab - identified by US officials as the man who set a fire on a Detroit-bound jetliner - said his son had been a student in London, but had left the city to travel.

Mutallab is accused of trying to destroy Northwest Airlines Flight 253, which was minutes away from touching down in Detroit after leaving Amsterdam earlier on Christmas Day.

British police searching London apartments (Photo: AFP)

Home Secretary Alan Johnson called the thwarted attack a "potentially serious security threat" and said British investigators were working with their American counterparts. Prime Minister Gordon Brown said he had spoken with the head of London's Metropolitan Police about the incident.

University College London said that while they could say that a student with a very similar name had attended the school, "it must be stressed that the university has no evidence that this is the same person currently being referred to in the media."

Boosting airport security

Officers from the Metropolitan Police - the force is involved in most of the major terrorism investigations in Britain - went in and out of an imposing white stone apartment block in a well-to-do area of central London. A police spokeswoman said the force was carrying out searches in connection with the incident in Detroit, but would not say if the searches at the building were connected.

At London's Heathrow Airport - one of Europe's busiest - security measures for travelers to the US were tightened at the request of American authorities.

British Airways said all carriers were asked to revise their security arrangements, which would include additional screening passengers and their hand luggage. The airline restricted carryon luggage to one bag per passenger - and let travelers know about the before they arrived at the airport.

A spokesman at London's Central Mosque, one of London's largest, said Mutallab was not known in the mosque.