Two men aged 29 and 30 and a 28-year-old woman, all from Keighley, are among the five suspects being questioned by the North East Counter Terrorism Unit following the arrests on Saturday, West Yorkshire Police said.
A 16-year-old boy from Swindon and a 28-year-old man from Anglesey are also being questioned.
All five were arrested on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism under section 41 of the Terrorism Act 2000 and currently remain in custody.
Courts on Sunday approved an extension for detectives to carry out their enquiries, giving them until May 8 to question the five.
Searches of a property in Keighley, which was attended by the Explosive Ordnance Disposal Unit on Saturday, meanwhile remained ongoing.
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