LONDON (AP) – British authorities yesterday identified 19 of 24 arrested in connection with an alleged plot to destroy US-bound commercial jetliners and froze their assets, while investigators probed their movements, backgrounds and finances.

Many of the names released by the Bank of England, acting on an order from the government, were of Muslim origin, many of which are common in Pakistan. The suspects ranged in age from 17 to 35.

Authorities said Thursday the plot would have caused “mass murder on an unimaginable scale”. At least one of the 24 people arrested was reportedly a woman with a small child; another was a convert to Islam.

The Metropolitan Police said yesterday that one of the 24 people was released without being charged.

Police did not identify the person who was released, nor did they say if the person remained a suspect. Twenty-two of the others had their detentions extended through to Wednesday. The final person’s detention hearing was delayed until Monday, but the suspect remained in custody.

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.

Investigators, describing a plot on the scale of the September 11 attacks in the United States, said the attackers planned to use common electronic devices to detonate liquid explosives to bring down as many as 10 planes.

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

A US law enforcement official in Washington said that at least one martyrdom tape was found during ongoing raids across England.

The Guardian newspaper, citing unidentified British government sources, said that after the first two arrests were made in Pakistan, 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.

Authorities pressed ahead with efforts to smash the purported terror ring. Two US officials said British, US and Pakistani investigators were trying to trace the steps of the suspects in Pakistan and were seeking to determine whether a couple of them attended terrorist training camps there.

Many of the suspects were said to be British Muslims and neighbours said at least two were converts to Islam.

Raids were carried out at homes in London, the nearby town of High Wycombe and in Birmingham, central England. Police still guarded homes in High Wycombe, where the Muslim community expressed shock and anger at being thrust into the international spotlight.

“They are considered ordinary British Muslims and they haven’t caused any harm to anyone,” accountant Mohammed Naeem said of those arrested. “They come from decent families.”

Naeem said that the Muslim community supports efforts to promote security, but that the police have acted on faulty intelligence in the past. He cited a recent raid in London in which police were forced to apologise for shooting an innocent Muslim man.

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

Neighbours identified another suspect as Don Stewart-Whyte, 21, from High Wycombe, a convert who changed his name to Abdul Waheed. Ibrahim Savant, of Walthamstow, one of the names on the Bank of England list, was a convert formerly known as Oliver, neighbours said.

The US television network CBS reported that one of those arrested worked at Heathrow Airport.

A British police official, speaking on condition of anonymity because of the sensitivity of the investigation, said the suspects were “homegrown”, though it was not immediately clear if all were British citizens.

Tariq Azim Khan, Pakistan’s minister of state for information, said: “These people were born and brought up in the United Kingdom. Some of them may have parents who were immigrants from Pakistan.”

Police would not say where the suspects were being held – which is not unusual in highly sensitive cases – but terrorist suspects are usually brought to the high-security Paddington Green police station, in central London.