LONDON – A British court yesterday extended the time nine suspects in the alleged plot to blow up U.S.-bound flights can be held without charges being filed against them, officials said.

Another suspect was expected to face a custody hearing Thursday, while an 11th person was released without charge.

Police said eight suspects who have not been charged could be kept in custody until Aug. 30, giving police more time to quiz them about the plot they have said involved liquid-based explosives, while the ninth suspect had his detention extended until Thursday.

The 11 were among about two dozen people arrested Aug. 10 in police raids in London, Birmingham and High Wycombe, about 30 miles northwest of the capital. The others arrested have either been charged or released.

Yesterday’s court action represented the first time that police have used new anti-terrorism laws to hold suspects for more than 14 days without charge, Britain’s Home Office said. The law lets officers make applications to hold terrorism suspects for a maximum of 28 days before filing charges.

Among those involved in the court action yesterday was a suspect identified as Umair Hussain. His attorney, Timur Rustem, said Hussain was ordered held until Thursday by a high court judge. Rustem said the judge dismissed a request that he be held for a week.

“It is good to see the system works, where a High Court judge can in some cases grant the full seven days but at the same time use discretion where, for example, it’s only a circumstantial case,” he told reporters.

Eleven others charged in the alleged terror plot appeared before a court for the first time on Tuesday.

Eight of the men charged were accused of offenses of conspiracy to murder and preparing to commit terrorism. Three others – including the mother of an 8-month-old – are charged with lesser offenses, including failing to disclose information.

British detectives are attempting to stitch together thousands of pieces of information to demonstrate they thwarted a major terror plot.

Officers yesterday began searching for evidence in an area of woodland in High Wycombe, a police spokeswoman said.

Months of surveillance had produced “significant video and audio recordings” regarding the alleged plot, London’s anti-terrorism police chief Peter Clarke said Monday.

He said investigators had found bombing-making chemicals, including hydrogen peroxide, as well as electrical components.

More than 8,000 items of data storage, such as compact discs, DVDs and memory sticks, were found. Maps of Afghanistan, suicide notes and books on explosives also were seized, officials said.

Investigators said the evidence was still being examined, including fingerprints, DNA samples and handwriting.

British officials also confirmed the plot involved the manufacture of liquid explosives, which would then be assembled and detonated on board airliners.

Investigators have not revealed if the alleged airline plot suspects were linked to al-Qaida.

Pakistani officials have linked people arrested there over the alleged conspiracy to al-

Qaida militants.