COUNTER terrorism police have taken over the investigation into an incident that prompted two evacuations and a controlled explosion at Newcastle University.
Two 18-year-old Russian students from the university were arrested after "suspicious material" was found.
Tonight police confirmed the North East Counter Terrorism Unit is leading the inquiry.
They disclosed that one of the teenagers was arrested in London on Tuesday on suspicion of offences under the Terrorism Act, while the other was held in Northumbria on Wednesday on suspicion of offences under the Explosives Act.
The suspects are still in custody and officers have been given more time to question them.
A police spokesman said: "Due to the potential offences under investigation, the North East CTU will lead the inquiry at this time.
"There is no evidence to suggest that students, or any wider communities are at immediate risk in connection with the alleged offences under investigation."
"We recognise that people may have concerns as a result of this activity and would like to reassure them that precautions were taken at the earliest opportunity to ensure public safety while inquiries were undertaken.
"We would ask people not to be alarmed and we are grateful for the patience and understanding of people locally."
Police asked students to leave their accommodation on Tuesday and carried out a controlled explosion.
A second temporary evacuation was ordered early this morning but searches have now concluded and students have been allowed to return.
On Tuesday the roads surrounding the INTO accommodation building were closed off as specialist bomb disposal experts were called in.
A specialist robot was seen entering the building and eventually a controlled explosion was carried out on Newcastle Town Moor.
Yesterday Dr John Hogan, registrar at Newcastle University, said they had excellent security arrangements in place.
"We'd like to reassure staff and current and prospective students that our main campus is open as usual today," he said.
"We would reiterate that our campus is very safe.
"We have excellent security arrangements in place at the university and that allowed us to deal with the issue very quickly."
Last night it emerged that police were called in by university staff on Tuesday morning amid concerns about a "change in behaviour" of a student and the belief he was carrying a knife.
Jo Farrell, assistant chief constable at Northumbria Police, confirmed that the counter terrorism unit is now leading the investigation.
She said: "To ensure you have a full understanding of the activity over the last few days I would like to outline the steps we have taken and provide reassurance.
"Shortly after 10am on Tuesday, June 10, 2014, Northumbria Police were contacted by staff from Newcastle University outlining concern in relation to a student.
"This concern was in relation to a change in the behaviour of the student and the belief he was carrying a knife.
"A University Neighbourhood Police officer attended and met with staff and as a result of that meeting the officer and staff attended a bedroom in the halls of residence.
"A number of items were seen in the bedroom which gave cause for concern and we implemented our well established response plans which included an evacuation of the building and implementation of safety cordons."