Police have again sealed off part of Newcastle University in connection with "suspicious items" found earlier this week.
Two 18-year-old Russian students studying at the university were arrested after bomb disposal units were called in and a controlled explosion was carried out.
Northumbria Police said this morning another cordon has been put in place.
A police spokesman said: "This is in connection with the original investigation at Newcastle University."
Students and staff were evacuated from the INTO building after concern was raised on Tuesday and specialist officers were called in.
Roads around the building were closed off and a bomb disposal robot was seen entering the premises.
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."
Chief Superintendent Laura Young said: "Police are continuing to investigate the incident at Newcastle University on Tuesday June 10.
"Two men aged 18 arrested in connection with this investigation remain in custody helping with enquiries.
"Overnight a small amount of a potentially suspicious substance has been recovered from the same location and will be removed from the building in due course. The building has temporarily been evacuated as a precaution and EOD are in attendance at the university building.
"The ongoing activity is necessary to support the investigation, which centres around explosive offences linked to substances recovered from the university.
"We're working closely with Newcastle University to keep disruption to a minimum for staff, students and members of the public.
"We must stress that this is the usual procedure in such investigations."