"There are a number of people now being interviewed as part of this investigation; it doesn't mean that they're all suspects but it is quite a complex investigation and the links to the U.K. are becoming more concrete," said Australian Federal Police Commissioner Mick Keelty.
Muslim groups in Britain placed advertisements in British national newspapers in praise of the emergency services and to declare that terrorism is "not in our name," borrowing the slogan from the mass protests in Britain against the invasion of Iraq.
The ads from the Muslims United coalition also quoted the Quran: "Whoever kills an innocent soul, it is as if he killed the whole of mankind. And whoever saves one, it is as if he saved the whole of mankind."
Britain's investigation into the three failed attacks in London and Scotland comes as the country is preparing several small ceremonies on Saturday to mark the second anniversary of London suicide bombings that killed 52 people and wounded more than 700 on July 7, 2005.
Separately, an immigrant to Britain who collected information about staging terrorist attacks was sentenced to nine years in prison Friday. Omar Altimimi, 37, came to England from the Netherlands in 2002 and applied for asylum, but police have been unable to establish his true identity or nationality, prosecutors said.
He was convicted earlier this week of six counts of possessing material of use to terrorists and two counts of money laundering.
"You were indeed, as the prosecution contend, a sleeper for some sort of terrorist organization," said Judge David Maddison. "It is not known, when, if and how you might have been called upon to play your part."
The manuals in his possession included instructions on using gas canisters to make car bombs, prosecutors said, but there was no indication that Altimimi had any connection to the failed bombing attempts in London and Glasgow.
His co-defendant Yusuf Abdullah, 30, a native of Yemen who pleaded guilty to two counts of money laundering, received a two-year sentence.
Maryclaire Dale reported from Philadelphia. Associated Press writer Rod McGuirk contributed to this report from Canberra, Australia.