Bomb experts have carried out a controlled explosion at a house after a "number of suspicious items" were found inside.
Northumbria Police say the Explosive Ordnance Disposal Team (EOD) has entered the address in Lake Avenue, South Shields.
The EOD are still examining other items in the flat and will dispose of them appropriately.
It comes after residents were evacuated from their homes in the early hours of today.
Chief Superintendent Ged Noble said efforts were ongoing to find those who live at the house.
No one has been arrested in relation to the incident.
He said: "We need to speak to the occupant of the address, but we may need to speak to other people."
A force spokesman said: "We would like to thank everyone for their patience while we make the flats safe.
"Currently this is being treated as a local incident and extra patrols remain in the area. "
A cordon remains is in place in the Lake Estate and police were called at around 4am after reports of a number of suspicious items.
Around 100 homes have been cleared by police.
A Northumbria Police spokesman said: "There is not believed to be any danger to the wider public but extra patrols remain in the area to carry out enquiries and reassure any concerned residents in the area."
Councillor Tracey Dixon, who represents the ward on South Tyneside Council, has told residents they can go to Temple Park Centre while the incident is ongoing.
A spokesman for South Tyneside Council said: “We are supporting residents who have been evacuated.
“The Waterline Suite in Temple Park Leisure Centre is currently being used as a rest centre for residents who have been moved from their homes and who cannot stay with family members or friends.
“Food and drink will be made available.
“We are liaising with the emergency services and will continue to monitor the situation.”
Elsie Manning, who lost her daughter Staff Sgt Sharron Elliott, 34, when her boat was blown up near Basra in November 2006, was one of those moved from her home.
She said: "At 6.20am there was a bang on the door and I opened it to find a policeman standing there.
"It was horrible, all the memories came flooding back.
"I just thought 'What's happened to my kids?'"
Alan Hall, of Cliffside, is among those who have been told to leave their homes.
The 47-year-old said: "We had a knock from the police telling us to evacuate within the next five minutes.
"If you look down the street, you can see the blue lights and all the tape.
"I can see it down Lake Avenue and across the street.
"The police are not telling us anything."
Cleaner Carol Jones, 56, and her son Thomas, 17, were also among those woken by officers.
Carol, who has since headed to work, said: "We were kicked out of bed just after 6am.
"I heard them braying on the door.
"I went down and saw the officer at the door and got a shock.
"He said 'Sorry to disturb you madam, but can you get your family dressed and leave the property as soon as possible, there's a major incident just around the corner.'
"And I just thought 'What's going on?'
"He said he couldn't give us any further details, but there was a risk to the public.
"I'm lucky I have a car.
"I took Thomas round to my daughter's and I pulled up outside and rang to tell her I was at the door.
"She panicked and flew down the stairs, but I told her what had happened.
"I've had a phone call from a friend who said she'd heard there was explosives.
"We should get a phone call when we can go back."
Gale Spencer, who lives in Lizard Lane, is rallying round to ensure residents can keep warm.
She is welcoming people into her home to offer them hot drinks and the chance to use the toilet if they cannot get into their own house while the alert is ongoing.
Jacqui Lamb, her husband, and their sons Elliott, 23, and Ethan, 10, moved out of their home on the estate after they grew concerned about their safety, but live beyond the cordoned.
Jacqui said: "My husband took the dog for a walk and saw there was lots of police activity and came back.
"We thought we'd better move."
One man, who is in his 40s, is among those asked to leave their house.
He said: "I'm furious.
"We've been evacuated in the early hours and some people are old.
"I've seen people been wheeled out in their wheel chairs, but there's no where to go.
"This has been going on for a while and we're stuck."