Police are searching a number of properties in central London as a man is charged with trying to blow up a US airliner flying to Detroit.Umar Farouk Abdulmutallab, 23, from Nigeria, is alleged to have had an explosive device hidden in his clothes. He is said to have been an engineering student at University College London.
The Metropolitan Police have been searching a flat at an apartment block in Mansfield Street, central London, and other properties in the capital. Police have cordoned off Mansfield Street in front of the apartment block.
Nigerian former banker Alhaji Umaru Mutallab said he believed the man was his son. Mr Mutallab said his son Umar had studied in London before going travelling. His son had not lived in London for some time and he was not sure of his whereabouts, he added.
He said: "I believe he might have been to Yemen, but we are investigating to determine that."
A spokesperson for University College London (UCL) said a student called Umar Farouk Abdulmutallab was enrolled on a mechanical engineering course between September 2005 and June 2008. It added: "It must be stressed that the university has no evidence that this is the same person currently being referred to in the media."
BBC security correspondent Gordon Corera said the British authorities were informed of a possible connection to the UK on Friday evening. It is understood one of their key priorities will be to check whether the arrested man has cropped up in the course of any other investigations.
BBC News correspondent Richard Slee said there was fairly low-key police activity at the last known London address of Mr Abdulmutallab, a basement flat in the block near Harley Street. Reporting from the scene, he said police forensic officers had been seen going into the building.
A blue English Heritage plaque states that philanthropist Sir Robert Mayer once lived in the block where properties have recently sold for between £1.5m and £2.5m.
The Metropolitan Police said its officers were liaising with the US authorities.
A Scotland Yard spokeswoman said: "Searches are being carried out at addresses in central London."