A US terror suspect turned state's evidence is being questioned about a man being sought over the bomb attack in London which killed 52 people.
James Ujaama, a Muslim convert from the West Coast city of Seattle, Washington was once charged with trying to set up a terror training camp in Oregon
He was charged in 2002 with trying to set up the camp for Muslim cleric Abu Hamza al-Masri. He pleaded guilty to lesser charges in exchange for co-operating with terror investigations until 2013.
Federal law enforcement officials said he is now being questioned about Haroon Rashid Aswat, who has been implicated in the plan to establish a training camp six years ago in Bly, Oregon.
British authorities are looking into whether Aswat had been in contact with the suicide bombers just before the July 7th attacks. They have also asked Pakistani authorities to search for him.
The officials did not say whether Ujaama has provided any useful information and his lawyer refused to comment.
Masri is the former the head preacher at London's Finsbury Park mosque, and also faces British charges of incitement to murder. He is being held in England.
Aswat is one of two al-Masri associates who are referred to but not named or charged in the indictment of Ujaama by a federal grand jury in Seattle, officials said. The other is Oussama Kassir, a Lebanese-born Swede, who was found guilty of weapons violations in Sweden in 2003.
Meanwhile, British police say they have received around 500 responses to their appeal for information about Thursday's attacks after they released photographs of four men they wanted to question.