Residents say armed police swooped on a house in a Houghton street earlier today.
People living in Cathedral View, Newbottle, saw a number of armed officers in the area at about 10am on Sunday.
No details have been released by police as yet.
One man who did not want to be named told the Echo: "The armed response unit was there and at the top of the estate too.
"The west side of the estate was cordoned off completely from the deli on Sunderland Road, cutting the estate in half.
"It's a nice estate really so I'm not sure what it is that's going on."
Another man who lives in the area said: "I didn't see the armed police but I saw a car getting towed away at about 1pm.
"It had blue tarpaulin over the top of it.
"It's normally a quiet area, but the police have been coming around a lot recently for some reason."