Police who arrested a teenager in an incident which led to families being evacuated from their homes found five viable explosive devices, a firearm and ammunition.
Around 50 people had to leave their homes in Newcastle upon Tyne, after the 18-year-old man was held at around 11.30am yesterday.
Officers said they suspected he was intending to harm people. He remains in police custody.
Chief Constable Sue Sim, of Northumbria Police, said there was thought to be a specific target, but would not say what it was.
Someone saw something that the man had written on Facebook, became concerned for his welfare and called the police.
Police went to check that he was all right and found the explosive devices, firearm and ammunition.
They have applied to magistrates for a 36-hour extension of his custody to continue questioning him.
Nikola Smith, who has lived on the street for six years and has four children, said she first knew about the incident when police knocked on her door and told her she had to leave.
The 36-year-old waitress said: “I got a knock on my door about 2pm and a policewoman said ‘you need to leave now’. She said ‘I can’t tell you about what’s going on’.
“I said ‘I have a one-year-old’ so she said ‘grab one bottle and then leave’. It was quite dramatic.”