A terror suspect from Middlesbrough will face up to five extra days of questioning.
Counter-terrorism officers were granted approval this morning to keep the 21-year-old in custody until Saturday before either charging, releasing or applying for even more time.
Counter Terrorism Policing North East confirmed a court had granted a "warrant of further detention" to allow them to keep him in custody.
The specialist unit raided a house in Teesville and three others - one in north London and two others in Middlesbrough - on Saturday morning.
Neighbours would later find out it was part of a massive "intelligence-led" operation following the arrest of a Middlesbrough man in the capital. The man was detained under the Terrorism Act on suspicion of "being involved in the commission, preparation or instigation of acts of terrorism".
Police spent hours searching the contents of the house until the discovery of "potentially suspicious items" inside saw bomb disposal experts drafted in.
Officers have up to 14 days to question people under the Terrorism Act but this is subject to continual review by the courts.