U.K. Bank Freezes Assets of 19 Terror Suspects

At the Justice Department, prosecutors have debated and identified possible criminal charges that could be filed against the suspects because they were targeting U.S.-bound flights. One official said they would defer to British prosecutors in the case but wanted backup options for the United States in case their London counterparts encountered problems.

U.S. officials said

In London Friday morning, British Home Secretary John Reid praised the help investigators had received from Pakistani security officials in their investigation, which started with a vague tip after the last summer's bombings on London's transit system.

Reid reiterated that British police believe they have all the main suspects in custody. Nonetheless, he said, the country's alert level would remain at "critical" because officials wanted to "err on the side of caution." He added: "There's never 100 percent certainty with these things."

Reid also stressed that officials were not casting blanket blame on Britain's Muslim community, saying that all people were victims in terror attacks that do not differentiate between people based on their religion or ethnic background.

The distinction was not between people of different religions and nationalities, he said, but between "the evil or terrorism and all civilized behavior."

U.S. intelligence officials have said there are strong indications of an al-Qaeda link to the plot.

In Italy, police rounded up about 40 people in a security crackdown, but the arrests appeared to be unrelated to the alleged plot in Britain.

Travelers continued to adjust to the new conditions at airports in the Washington region and in the United Kingdom.

For the most part, travelers seemed to have come prepared for a new travel experience, and were checking bags they might have otherwise carried and packing gels, liquids and toothpaste into checked baggage as required by restrictions imposed Thursday .

At Reagan National , Chertoff said officials were preparing "refinements" to the restrictions in an attempt to move travelers more quickly through checkpoints. "We're going to move to try to make this as simple and as easy as possible as quickly as possible," he said.

But Chertoff said a tour of the airport Friday indicated that "things are moving well."