LONDON - Muslim extremists are plotting at least 30 major terrorist attacks in Britain and the threats may involve chemical and nuclear devices, the head of Britain's domestic spy agency said.

Director General of Britain's MI5 Eliza Manningham-Buller in Birmingham, November 8, 2004. Muslim extremists are plotting at least 30 major terrorist attacks in Britain and the threats could involve chemical and nuclear devices, Manningham-Buller said on Thursday evening. [Reuters]

Eliza Manningham-Buller, head of intelligence agency MI5, said young British Muslims were being groomed to become suicide bombers and her agents were tracking some 1,600 suspects, most of whom were British-born and linked to al Qaeda in Pakistan.

"We are aware of numerous plots to kill people and damage our economy. What do I mean by numerous? Five? Ten? No, nearer 30 ... that we know of," Manningham-Buller said in a speech to a specially invited audience in London on Thursday evening.

Her remarks were posted on the MI5 Web site on Friday.

"These plots often have links back to al Qaeda in Pakistan and through those links al Qaeda gives guidance and training to its largely British foot soldiers here," she added.

The threat was growing and affected other countries from "Spain to France to Canada and Germany," she said.

Britain suffered its worst peacetime attack in July 2005 when four British Islamists blew themselves up on London's transport network, killing 52 commuters and wounding hundreds.

"This is a threat that has grown up over a generation. I think (Manningham-Butler)'s absolutely right in saying it will last a generation," British Prime Minister Tony Blair told reporters.

Blair said it could only be combated by tough terrorism laws and fighting "poisonous propaganda" influencing young people.

The government has said law and order will be a major part of the next parliamentary session and tougher security measures are expected to be outlined in a speech next Wednesday.

NUCLEAR TECHNOLOGY

Islamic Human Rights Commission chairman Massoud Shadjareh disputed figures quoted by the spy chief, saying that out of more than 1,000 people arrested under terrorism laws, only 27 have been convicted, and only 8 were Muslims.

"Although we recognize that there is a real threat, the suggestion that we could even face a nuclear threat will only contribute to paranoia rather than safety and security."

Anti-terrorist police say they have thwarted at least five major plots since last year's attacks. In August, police said they foiled a plot to blow up transatlantic airliners using liquid explosives.

This week, British Muslim convert Dhiren Barot was jailed for 40 years for planning to blow up the New York Stock Exchange and carry out attacks in Britain using a "dirty bomb."

Manningham-Buller, who rarely speaks in public, said her officers and the police were dealing with some 200 groupings or networks and some 1,600 identified people "actively engaged in plotting or facilitating terrorist acts here and overseas."

While militants may use now use home-made improvised devices, the threat in the future "may include the use of chemicals, bacteriological agents, radioactive materials and even nuclear technology," she said.

The number of cases being pursued by security services had risen by 80 percent since January, she added.

"That's significant. What she's trying to indicate is the nature of the threat is evolving faster than MI5 can easily track it," said Michael Clarke, professor of defense studies at King's College in London.

While Blair has rejected the argument that British foreign policy is to blame for the terrorist threat, Manningham-Buller said the wars in Iraq and Afghanistan seemed to play a part, as shown in so-called "martyrdom" videos.

"The extremists are motivated by a sense of grievance and injustice driven by their interpretation of the history between the West and the Muslim world," she said.