LONDON (AP) — British officials on Friday identified 19 of the 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 saw shorter lines at airports as flight schedules slowly returned to normal.

British police have arrested 24 people suspected of involvement in the plot. At least one was reportedly a woman with a small child; two others were converts to Islam. One of the suspects reportedly worked at Heathrow Airport.

The Bank of England said it had frozen the accounts of 19 people arrested Thursday. The men, ranging in age from 17 to 35, had names of Muslim origin, many of them common in Pakistan.

In addition, five Pakistanis have been arrested in Pakistan as suspected "facilitators" of the plot, a government official said, as well as two Britons arrested there about a week ago.

Investigators, describing a plot on the scale of the Sept. 11, 2001, attacks, said the planners sought to use common electronic devices to detonate liquid explosives to bring down as many as 10 planes.

The bombs were to be assembled on the aircraft, apparently with peroxide-based solution and everyday carry-on items such as a disposable camera or a music player, two American law enforcement officials told The Associated Press. The officials spoke on condition of anonymity because Britain asked that no information be released.

A federal law enforcement official in Washington said 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-Qaida.

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 they served as local "facilitators" for the two Britons, the official said. It wasn't clear when they were detained.