British and Pakistani investigators are tracking possible links between a group of local Muslims and suspected terrorists in Pakistan who allegedly planned to blow up as many as 12 passenger planes leaving from London-area airports.
Officials said they believed they have arrested the principal figures in the planned terrorist attacks after a series of raids in Britain and Pakistan. But they said that airports would remain at high alert for the foreseeable future.
"We believe it was a major, major plot," said Home Secretary John Reid, in a television interview on Sunday. He said "the main targets" were in custody, but he warned that other operatives might still be at large.
The arrests of two dozen people in Britain, all of them apparently British citizens and most of Pakistani descent, in connection with the alleged bombing scheme have once again raised concern about the alienation of some of the country's 1.7 million Muslims. And the plot's threads back to Pakistan are likely to further concerns that the South Asian nation has become a hub for international terrorism.
As was the case following last July's bombings in London, which were attributed to British Muslims, the arrests have also spurred some disbelief. Several of the suspects, in the words of their neighbors, were "football and fish-and-chips" men, devout but not murderous. Some British Muslims have complained that they have become the targets of over-zealous police surveillance and have been stereotyped as fanatics because of the radical actions of a tiny minority.
Early Thursday, British police arrested 24 people in raids on a neighborhood in east London, the small town of High Wycombe and Birmingham, in connection with the alleged bombing plot. One person was subsequently released, a police spokeswoman said. She would not provide any details.
Over the weekend, police also raided several Internet cafes, removing hard disks and other material, and carting away documents, computers, and electronic equipment from homes and businesses associated with the suspects.
In an unusual move that drew criticism from some quarters, the Bank of England also published the names of 19 of the suspects and announced it was freezing their assets. Those identified ranged in age from 17 to 35, with most appearing to be the children or grandchildren of Pakistani immigrants.
British newspapers reported that at least two of the suspects were recent converts to Islam.
While several of those arrested lived in the same neighborhoods, it was not immediately clear whether all of the suspects knew each other. That would not be unusual, according to terrorism experts. To reduce the possibility of having a plot discovered, individual operatives may be kept in the dark about others involved.
Some of the suspects had been under surveillance since last December, when British authorities received a tip about their contacts with people in Pakistan, according to an intelligence source in London.
Some of the biggest leads in the case are believed to have come through cooperation with Pakistani officials. Last week, a British citizen of Pakistani origin named Rashid Rauf was arrested in the city of Bahawalpur in southern Punjab state. Mr. Rauf, a brother of one of the suspects arrested in England, has been described in some media reports as having connections to Al Qaeda and the Pakistani militant group Jaish-e-Muhammed (based in Bahawalpur), and is believed to have been in Pakistan to raise funds and to consort with other militants in plotting the scheme.
In an interview on Sunday, the Minister of Interior Aftab Ahmed Sherpao said he could not say with certainty whether Rauf was an Al Qaeda operative, but maintained that so far as the plot was concerned, "the linkages with Al Qaeda are there."
Some media reports also said that an unidentified man arrested several weeks ago at the Pakistan-Afghan border tipped off Pakistani authorities to the possibility of a large-scale attack in England involving several jetliners. Rauf has also been described in some reports as having been arrested at the Afghan border. Mr. Sherpao, however, denied these reports.
Beyond Rauf, Pakistani authorities say the half-dozen other suspects in custody include one other British national. Tasneem Aslam, the spokesperson for the Foreign Office, would not say exactly where the suspects were apprehended. The suspects are described as "facilitators," perhaps providing housing or other low-level logistical support. At least 17 suspects are now under questioning, according to the Associated Press.
Some media reports have suggested that two or three major suspects are still on the loose, including Matiur Rehman, considered a senior figure linked to Al Qaeda. Ms. Aslam, however, dismissed this claim as speculation.
Sherpao and other government officials would not disclose precisely how Rauf's arrest prompted the swift crackdown in England, saying only, "The cooperation [with Britain] was there before [Rauf's] arrest and after his arrest. We have been exchanging notes for some time."
Pakistani authorities were quick to trumpet their role in thwarting the terrorist plot, but analysts in Pakistan say Islamabad is still likely to face diplomatic fallout.
"There will be diplomatic pressure, with the US arguing that this incident shows that ... Pakistan has to go after terrorists with more pressure," says Hasan Askari Rivzi, a political analyst based in Lahore.
Mr. Rivzi and others argue that the London plot, the latest in a long stream that has implicated Pakistan, negates the argument that Pakistan is no longer used by international groups as a hub for terrorist activity. "That argument can now be challenged very easily," Rivzi says, adding, "It is an embarrassment for the government of Pakistan."
Others have taken a more sympathetic line, saying that the plot merely reinforces how difficult a task the Pakistani state is faced with: flushing out terrorists in rugged mountains, along porous borders, and in teeming cities, where ideological sympathies and rough terrain allow them to operate virtually invisibly. "This event shows how much more complex the problem has become," even though Pakistan is genuinely cracking down, says Lt. Gen. (ret.) Talat Masood.
Militant factions have splintered, gone underground, or assumed new names, many of them able to operate independently without an overarching leadership, making the task of identifying and neutralizing them more difficult, analysts say.
Still, Mr. Masood marveled at how frequently Pakistan has been implicated as a base for terrorist activity. "It's so astonishing that there is always a Pakistani connection. It shows that something is wrong. Is it that there is no governance left in this country? Is the government so lax at the grass-roots level, the provincial level? It seems like that."
Sherpao, for his part, maintained that the suspects involved in the plot were not Pakistani, but British.
Several of the arrests in Britain took place in High Wycombe, a small town surrounded by wooded hills 25 miles west of London.
The population, as in so many places in Britain, is mixed. Indian restaurants abut pubs and Chinese takeout shops. Up the hill from a large green-domed mosque, the White Horse tavern advertises "exotic lap dancing." A sign outside warns, "Do not enter if you are offended by nudity."
Naseem Saddique, a student whose parents emigrated from Pakistan 30 years ago, says he has a hard time believing that the town sheltered religious radicals plotting terrorist actions.
"People here are hard-working," he says, as he shopped for a cheap set of tools at the covered market on Saturday. "They don't get involved in crazy things like that. I think there must have been some big mistake in the intelligence. It's happened before."
Many people in Britain, Muslims and non-Muslims alike, are skeptical of what the police call their antiterrorism drive, in part because of a bungled police raid on a British Muslim family earlier this year.
But the latest arrests also underlined the polarization of many Muslims. A number of opinion polls over the past year have found that a substantial minority would like to see Islamic law instituted in heavily-Muslim areas of Britain and that nearly half identified themselves as Muslim first and British second. Some 10 percent in some surveys also justified or said they understood the motivations of the London bombers.
However, surveys also show that most British Muslims favor a crackdown on those advocating violence within their community.
Leaders say that they recognize they have to work harder to counter radicals, but say their job has not been made easier by perceptions that British foreign policy is stacked against Muslim causes.
A man who gave his name as Abu Abdullhah appeared on Sky News television to argue that Muslims were justifiably angered by the Bush administration's goal of democratizing the Middle East.
"Democracy," he said, "is a crime in Islam" and "people who voted for Tony Blair are guilty" because of Mr. Blair's support for the American-led war in Iraq.
Some Muslim leaders say many second- and third-generation immigrants from Muslim countries look outside their families for religious guidance and fall under the sway of such militant ideas.
"You've got a community that comes from different areas of Pakistan, India, and Bangladesh, from predominantly rural areas," said Khalid Mahmood, a member of Parliament from Birmingham, where some of the suspects in the plane plot live. "So the older generation's understanding of Islam was descriptive rather than informed. So the new generation has been radicalized by people who purport to be informing them of their religion."
Before last year's bombings in London, British authorities tended to take a hands-off attitude toward home-grown radicals.
"The British were taking the view that, yes, we know there are radical elements of Islam, but as long as the government is tolerant of these people and doesn't oppress them, whatever problems they cause will happen elsewhere," says Bob Ayers, a terrorism expert with the Chatham House think tank in London. The London attacks brought about a dramatic shift. "Those events," says Mr. Ayers, demonstrated that this phenomenon of radical Islam would strike against the UK."