Police arrested seven people in southern England on Sunday in connection with the failed July 21 London transit bombings and reportedly were investigating the attackers' ties to Saudi Arabia and Italy.
Police raided two properties in Brighton, on the south coast, taking seven people into custody, a spokeswoman for the Metropolitan Police said, providing no other details about the arrests.
In northern Italy, police took a brother of one main suspect into custody for questioning Sunday, the Italian news agency ANSA said, but he was not accused of terrorism, ANSA said.
The arrests follow dramatic raids earlier this week in London and Rome that netted the four men police believe tried to set off bombs in three subway trains and a bus July 21, two weeks after the deadly July 7 attacks.
Police were searching for those who may have recruited and directed the bombers and built the explosives while also probing for links between the two terror cells, one made up mostly of Britons of Pakistani descent and the other mainly of east African-born Britons.
In Rome, investigators were interrogating Osman Hussain, 27, an Ethiopian-born British citizen suspected of trying to bomb the Shepherd's Bush subway station in west London.
Hussain was arrested Friday at a Rome apartment reportedly belonging to a brother after police traced calls he made on a relative's cell phone. Britain has requested his extradition for questioning, and an initial hearing was held Saturday.
His attorney, Antonietta Sonnessa, said no formal charges had been filed against Hussain, adding that he was likely to fight extradition.
A brother, identified as Fati Issac, was detained Sunday in the northern Italian town of Brescia on suspicion of destroying documents sought by investigators, ANSA said.
CBS News Correspondent Elizabeth Palmer reports that police would have had a more difficult time catching Hussain had he exhibited the traits of a "hardened terrorist."
"The panic was evidenced by the behavior," said intelligence expert Bob Ayers, referring to Hussain's use of his cell phone to call his brother.
Palmer reports that investigators still face a troubling question: How did Hussain — whose picture was everywhere — manage to just get on a train and slip out of a country on full alert?
Police also discovered that Hussain called Saudi Arabia hours before his arrest, the Sunday Telegraph newspaper reported, and the Sunday Times said another bombing suspect went on a monthlong visit to Saudi Arabia in 2003, telling friends he was to undergo training there.
Hussain reportedly told investigators the bombers were motivated by anger over the Iraq war.
A legal expert familiar with the investigation told The Associated Press in Rome that Hussain admitted to a role in the attack but said it was only intended to be an attention-grabbing strike.
Hussain told interrogators he was not carrying enough explosives to "harm people nearby," the expert said, speaking on condition of anonymity because Italian law requires that the ongoing investigation remain secret.
Hussain also said the bombers had been led by a man called "Muktar," the Rome daily La Repubblica reported.
"Muktar showed us videos with images of the war in Iraq," Hussain said, according to Italian reports.
Suspect Muktar Said Ibrahim, 27, was arrested Friday in London. The Ethiopian-born Briton, also known as Muktar Mohammed Said, is accused of planting explosives on a bus in east London. The Sunday Times said he went to Saudi Arabia in 2003.
A second man arrested in London on Friday, who identified himself as Ramzi Mohammed, is suspected of trying to blow up a train at the Oval Station.
Another suspect, Yasin Hassan Omar, 24, a Somali with British residency, was arrested in Birmingham on Wednesday. He is suspected of trying to bomb a subway train near Warren Street station on July 21.
Spain's intelligence chief dismissed the possibility that the London bombings were connected to the train bombings in Madrid that killed 191 people last year.
Alberto Saiz, director of the National Intelligence Center, told the daily El Pais in an interview published Sunday that similarities between the attacks were limited to "their outward appearance" and the targeting of transport networks.
"At that point, the differences start," Saiz was quoted as saying. The July 7 group of London bombers was "small--just four people, less visible than the Madrid one."
"Two weeks later, they try a second episode of the same attack
obviously, the perpetrators are not the same," Saiz said.
"In contrast to Madrid, this gives us the feeling that they are coordinated with other groups or have direction from above, and that there is a plan," he added. "This is not an isolated group that decides to act on its own account."