U.S. & World

LONDON (CBS News) ― Investigators have uncovered no signs of U.S.-based terrorists linked to a plot to blow up airliners headed to the United States, Homeland Security Secretary Michael Chertoff said Friday.

"Currently, we do not have evidence that there was, as part of this plot, any plan to initiate activity inside the United States or that the plotting was done in the United States," Chertoff said, a day after British authorities announced the arrests of two dozen suspects.

The arrests led the Bush administration to put the U.S. on its highest threat alert on flights headed to the United States from the United Kingdom. Additionally, all other flights were raised to the second-highest alert level.

But Friday, Chertoff said his department was looking to adjust some of the new traveling restrictions -- they have barred many common carry-on items such as water bottles and toiletries -- to "somewhat reduce any additional inconvenience." He provided no details.

"I don't want to suggest that they're going to be earth-shattering, but we're going to move to try to make this as simple and as easy as possible, as quickly as possible," he said in a news conference at Reagan National Airport.

Even so, Chertoff cited the possibility of other terrorists or sympathizers, saying, "So I'm not prepared to let my guard down."

He said that over the longer term, officials would examine the threat involved in this week's plot -- some common chemicals, which combined can form a deadly explosives.

Officials will study "how we can calibrate our systems to take account of these developments, and then, with that in mind, try to ultimately come back to a regime of security that will give the maximum amount of freedom to the travelers," he said.

Meanwhile, British officials on Friday identified 19 of the 24 suspects accused of planning to blow up U.S.-bound aircraft in the biggest terrorist plot to be uncovered since 9/11, while investigators probed their movements, background and finances.

Travelers in Britain and the U.S. saw shorter lines at airports as flight schedules slowly returned to normal.

CBS News correspondent Sheila MacVicar reports all the suspects in custody in Britain are British-born and most are middle class of Pakistani descent. The youngest is 17. One is a pregnant woman and another a woman with a six-month old child.

CBS News confirmed that one of the arrested men was a Heathrow Airport worker taken from his home by police in his airport uniform.

The Bank of England said it had frozen the accounts of 19 of the suspects and, in a very unusual move, posted their names on its Web site.

In Pakistan, authorities arrested five people, bringing the total number of suspects held there to seven. A Pakistani official said the five Pakistanis were believed to have been helping two British citizens who were taken into custody there a week ago.

British officials said they are confident most of the main players have been accounted for.

Investigators said the attackers planned to use common electronic devices to detonate liquid explosives to bring down as many as 10 U.S.-bound jumbo jets. Security sources the would-be terrorists discussed blowing their bombs in midair over American cities, maximizing casualties in the air and on the ground, reports MacVicar.

A federal law enforcement official in Washington said that at least one martyrdom tape was found during raids across England on Thursday. Such a tape, as well as the scheme to strike a range of targets at roughly the same time, is a hallmark of al Qaeda.

"There's a lot to suggest to us this is an al Qaeda attack," Frances Townsend, President Bush's homeland security adviser, said on CBS' The Early Show. "We just need a little more time to put together those links."

British Home Secretary John Reid said Britain was grateful for Pakistan's cooperation and that officials believed the main suspects were in custody. However, the threat level in the U.K. remained at "critical," the highest level.

Agents in Pakistan arrested at least seven people, including two British nationals of Pakistani origin who provided information on the terror plot, a senior government official said Friday. The arrests were made in the eastern city of Lahore and in Karachi, the official said on condition of anonymity because he did not have the authority to speak formally on the issue.

Two were Britons arrested about a week ago, he said. The five Pakistanis were arrested on suspicion that they served as local "facilitators" for the two Britons, the official said. It wasn't clear when they'd been detained.

The Guardian newspaper, citing unidentified British government sources, said that after the arrests a message was sent to Britain telling the plotters: "Do your attacks now." That message was intercepted and decoded earlier this week, The Guardian said.

A U.S. congressman briefed by intelligence officials, who did not want to be identified because of the sensitivity of the investigation, said U.S. intelligence had intercepted terrorist chatter.

Meanwhile, airline passengers in Britain and the U.S. faced a second day of disruptions and disappointment as airports struggled to restore flight schedules.

"It is going to be another difficult day today, both for airports and for passengers, but there is cause for optimism that we will get more flights off today," said Stephen Nelson, chief executive of British Airports Authority, which runs Britain's major airports.

At Heathrow, Europe's busiest airport, around 70 percent of flights were running, and most inbound flights arrived on time, though flights from the United States — which increased security measures in the wake of the threat — were heavily delayed.

On Thursday, the U.S. issued its highest terrorism alert ever, red, for commercial flights from Britain to the United States and raised the threat level for all domestic and international flights. All other flights, including all domestic flights in the United States, were put under an orange alert, one step below the highest level.

The threat of liquid explosives led to a ban on carrying nearly any kind of fluid aboard an aircraft. Mothers tasted baby bottles in front of airport security guards to prove it contained milk or formula — not a component of an explosive.

By Friday morning, more passengers were prepared for the ban on liquids in carry-on bags and were packing items like makeup, perfume and suntan lotion in checked luggage instead.

That helped shrink the check point lines for flights to lengths closer to normal Friday morning at Miami International Airport, spokesman Greg Chin said. Passenger traffic was moving more smoothly at New York's major airports as well, and the flight delays Friday morning were generally no more than 15 minutes, said Tiffany Townsend, a spokeswoman for the Port Authority of New York and New Jersey.

The attacks were planned against commercial flights on U.S. airlines leaving within an hour of each other for the most popular American tourist cities: direct from Heathrow Airport in London to New York, Washington, Miami, Los Angeles, Chicago and Boston. Somewhere over the Atlantic Ocean, investigators say, the martyrs planned to simultaneously explode small chemical bombs made from ingredients in their carry-on luggage, CBS News correspondent Jim Stewart reports.

"This is not a case of wannabes fantasizing about an attack. We believe it was the real deal. To target multiple airlines with such a plan requires a sophistication that strongly points to al Qaeda," a senior U.S. official told CBS News.

The investigative file put together by Scotland Yard shows the case began three months ago when two British citizens of Pakistani descent traveled to Pakistan and met with Islamic extremists. Following the men led agents to their associates back in the London area (approximately 20 to 30 young men described as "disaffected" British nationals mostly of Pakistani descent). A British undercover agent apparently infiltrated the group, Stewart reports.

Then, two weeks ago it became apparent the group was targeting aircraft and the investigation took on new urgency. When investigators became convinced the men had picked their flights and bought battery-powered charging devices to set off their bombs, they moved in.

White House spokesman Tony Snow said, "There were some signs. They thought it was time to move," he said of British authorities.

London Deputy Commissioner Paul Stephenson said the arrests were made in London, its suburbs and in Birmingham, and that searches continue in a number of locations. "We are confident that we've prevented an attempt to commit mass murder on an unimaginable scale," Stephenson said.

Imtiaz Qadir, of the Waltham Forest Islamic Association, said one of the suspects was a woman in her 20s who had a 6-month-old child. "They have taken the child too, because it needs to be with its mother."

Neighbors identified one of the suspects as Don Stewart-Whyte, 21, from High Wycombe, a convert who changed his name to Abdul Waheed.

"He converted to Islam about six months ago and grew a full beard," said a neighbor, who refused to be identified. "He used to smoke weed and drink a lot but he is completely different now."

Ibrahim Savant of Walthamstow, one of the names on the Bank of England list, was a convert formerly known as Oliver, neighbors said.

The complete list of suspects whose assets were frozen follows, as released by the Bank of England:

1. ALI, Abdula, Ahmed
DOB: 10/10/1980
Address: Walthamstow, London, United Kingdom

2. ALI, Cossor
DOB: 04/12/1982
Address: London, United Kingdom, E17

3. ALI, Shazad, Khuram
DOB: 11/06/1979
Address: High Wycombe, Buckinghamshire, United Kingdom

4. HUSSAIN, Nabeel
DOB: 10/03/1984
Address: London, United Kingdom, E4

5. HUSSAIN, Tanvir
DOB: 21/02/1981
Address: Leyton, London, United Kingdom, E10

6. HUSSAIN, Umair
DOB: 09/10/1981
Address: London, United Kingdom, E14

7. ISLAM, Umar
DOB: 23/04/1978
Address: High Wycombe, Buckinghamshire, United Kingdom

8. KAYANI, Waseem
DOB: 28/04/1977
Address: High Wycombe, Buckinghamshire, United Kingdom

9. KHAN, Assan, Abdullah
DOB: 24/10/1984
Address: London, United Kingdom, E17

10. KHAN, Waheed, Arafat
DOB: 18/05/1981
Address: London, United Kingdom, E17

11. KHATIB, Osman, Adam
DOB: 07/12/1986
Address: London, United Kingdom, E17

12. PATEL, Abdul, Muneem
DOB: 17/04/1989
Address: London, United Kingdom, E5

13. RAUF, Tayib
DOB: 26/04/1984
Address: Birmingham, United Kingdom

14. SADDIQUE, Muhammed, Usman
DOB: 23/04/1982
Address: Walthamstow, London, United Kingdom, E17

15. SARWAR, Assad
DOB: 24/05/1980
Address: High Wycombe, Buckinghamshire, United Kingdom

16. SAVANT, Ibrahim
DOB: 19/12/1980
Address: London, United Kingdom, E17

17. TARIQ, Amin, Asmin
DOB: 07/06/1983
Address: Walthamstow, London, United Kingdom, E17

18. UDDIN, Shamin, Mohammed
DOB: 22/11/1970
Address: Stoke Newington, London, United Kingdom

19. ZAMAN, Waheed
DOB: 27/05/1984
Address: London, United Kingdom, E17

(© 2006 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)