POLICE are still quizzing the two men arrested in Halifax in early morning anti-terror raids.
They are being held in London "on suspicion of the commission, preparation or instigation of acts of terrorism".
Warrants for further detention for the two men, who are 25 and 29, mean police have until next Tuesday to hold them.
The warrants were granted by Westminster magistrates after an application from the Metropolitan Police.
Armed anti-terrorism officers from the Met, supported by colleagues from West Yorkshire, made the arrests in the Pellon area at about 6am on Tuesday.
Sources said the operation involved alleged extremist propaganda material used to spread radical Islamist ideo- logy.
Four properties in Halifax, as well as a flat in north London, were searched as part of the `intelligence-led' investigation, police said.
Meanwhile, anti-terrorism police in Manchester are continuing to question three men arrested on Tuesday in a separate, unlinked operation.
Two men aged 24 and a 32-year-old were arrested in dawn raids by armed police investigating claims the men helped a wanted terror suspect flee the country.
They were held as part of an inquiry into the disappearance of a man who was being monitored under a control order.
The man, thought to be 26 and of Pakistani origin, was wanted by police.
He fled from a Manchester mosque this month.
He was reported as saying he wanted to do terror training in Afghanistan.
He was placed on a control order - similar to a loose form of house arrest for people suspected of involvement with international terrorism - but absconded within four days.
Police traced him to a mosque but while they negotiated with community leaders over his release he slipped out of a rear entrance.
Anti-terror squad officers swooped on two addresses in the Cheetham Hill district of north Manchester and two in Longsight in the east of the city.
Armed officers burst into the houses shortly after 5am.
They arrested the 24-year-olds at a house in Heywood Street, Cheetham Hill. The 32-year-old was arrested at a house on Chaucer Walk, Longsight.
THE explosive used by the alleged July 21 bombers was so powerful it would have caused devastation, a court heard.
The alleged mix of hydrogen peroxide and chapatti flour, along with its TATP detonator, had a similar explosive strength to gelignite and TNT, according to forensic scientist Claire McGavigan.
She said the alleged bombs would have exploded at around 6km/sec, sending lethal shrapnel at "hundreds of metres a second".
Six men are on trial at Woolwich Crown Court accused of hatching an extremist plot to carry out a series of murderous suicide bombings on the London public transport system.
The jury heard none of four bombs set off in three tube trains and a bus on July 21 exploded properly.
Ramzi Mohammed, 25, of North Kensington, west London, is alleged to have tried to set off the first bomb on the Northern Line between Stockwell and Oval.