LONDON -- British police investigating armed Algerian groups suspected of planning an attack using the deadly poison ricin studied seized documents Tuesday and interrogated seven men, most of them North African, arrested in a raid on a radical London mosque.
A day after the raid, Prime Minister Tony Blair told lawmakers there was no doubt Osama bin Laden's al-Qaida terrorist network would try to attack Britain.
Blair said he thinks it's "inevitable" that al-Qaida will try in some form or other. "I think we can see evidence from the recent arrests that the terrorist network is here, as it is around the rest of the world," Blair said Tuesday.
Experts said Monday's early morning raid on the Finsbury Park Mosque marked a toughening of Britain's counterterrorism policy.
Dozens of officers used a battering ram to storm the red-brick north London mosque in the latest operation linked to the Jan. 5 discovery of ricin -- highly toxic poison extracted from castor beans -- in an apartment 2 miles away.
The seven suspects -- six North Africans aged 23-48 and a 22-year-old Eastern European who were arrested under the Terrorism Act 2000 -- were being questioned at a London police station. Officers have 72 hours before they must charge or release the men.
The mosque is known to be a center of radical Islam and, according to security officials, a fertile recruiting ground for extremists.
Previous worshippers include shoe-bomber Richard Reid and extremists who plotted to blow up the U.S. Embassy in Paris, officials say.
Intelligence agencies had the mosque under surveillance for months before the raid, and newspaper reports said Britain's MI5 domestic intelligence service had intercepted thousands of e-mails sent from computers there.
Since the ricin find, news reports have said security agencies are investigating a network of Algerian extremists in Britain, possibly linked to Algeria's radical Armed Islamic Group.
Algerian groups in Britain "are probably linked in inspiration" to al-Qaida, but not directly connected to bin Laden's terrorist network, Stevenson said.
Intelligence experts say some members have attended terrorist training camps in Afghanistan, where chemical and biological weapons like ricin may have been on the training agendas.
Algerian community leaders say dozens of Algerian extremists have come to Britain in the last few years to escape a crackdown by French authorities. Mohammed Sekkoum, head of the Algerian Refugee Council in London, has said that as many as 100 Algerian terrorists have entered Britain in the past two years -- to the alarm of most Algerians in the country.
France has criticized Britain in the past for failing to crack down on North African extremists on its soil. Britain's relatively liberal asylum laws and willingness to let exiled radicals continue their political activities have made it an attractive base for dissidents of all stripes.
But experts say extremists increasingly see Britain as a target, particularly given Blair's staunch support of the United States over the war on terrorism and Iraq.
Al-Masri, the Egyptian-born firebrand preacher who is wanted in Yemen on terrorist charges, was not arrested in the raid. Al-Masri denied any link with terrorist activities.
Five North Africans have been charged with chemical weapons offenses over the ricin find -- including 36-year-old Nasreddine Fekhadji, charged on Monday, who lived just around the corner from the mosque.
Kamel Bourgass, 27, has been charged with the murder of Detective Constable Stephen Oake, the policeman stabbed to death during a Jan. 14 raid in the northern city of Manchester.