British police are searching a property in southeast England amid reports that a man linked to bomb blasts in Stockholm, the Swedish capital, used to live in the area.
Officers from London's Metropolitan Police began the search just before 11:00 GMT on Sunday, a spokesman said, in the wake of the twin blasts which killed one person, thought to have been the bomber himself.
"Officers executed a search warrant under the Terrorism Act 2000 at an address in Bedfordshire," a spokesman said.
"No arrests have been made and no hazardous materials found," police added in a statement on Monday as they searched the terraced property, which has been cordoned off.
"We are confirming that this is in connection with the incident in Stockholm."
Media reports have suggested that the man believed to be behind Saturday's bomb blasts had studied and lived in Luton, a town north of London.
The explosions in Stockholm came as Christmas shoppers crowded in a busy quarter of the Swedish capital. Swedish police have announced that they are treating bomb blasts as a "terrorist crime".
Two people received minor injuries in the blasts, the first of which came from a car that blew up near Drottninggatan, a busy shopping street in the centre of the city.
Shortly afterwards, a second explosion was heard further up the same street and the body of a man was found on the ground.
Media in Sweden have named a 28-year-old man of Iraqi origin, who they say died in the attack, as the suspected bomber but Swedish police have refused to confirm the details.
Shumukh al-Islam, a pro al-Qaeda website, named Taymour Abdel Wahab as the man responsible for the explosions. But Sweden's intelligence agency Sapo would not confirm or deny that the man identified by the website was the bomber.
British media reported that he studied sports therpay at the University of Bedfordshire in Luton, around 50km north of London, and had continued living in the town in recent years.
The wife and children of Wahab - said to be in his late 20s - were reportedly still living in Luton, The Daily Mail and The Daily Telegraph reported.
Neighbours told The Telegraph that he had been seen at his house in Luton as recently as two-and-a-half weeks ago.
Britain's interior ministry refused to comment on the reports.
"We remain in close contact with the Swedish authorities," a spokeswoman told AFP news agency.
"It would be inappropriate to comment on an ongoing investigation at this time."
Umar Farouk Abdulmutallab, a 23-year-old Nigerian accused of trying to blow up a plane as it approached the US city of Detroit on Christmas Day last year, had also spent time in Britain, studying mechanical engineering at University College London.