Roads were sealed off and armed police patrolled a Sheffield suburb this morning.
They have since re-opened but police activity is still underway, with activity centred around the Burngreave Road, Nottingham Road and Rock Street area.
A number of police cars and vans parked up and police scenes of crime experts were at the incident.
Bus companies warned passengers to expect delays because of road blocks earlier today and Travel South Yorkshire, posting on Twitter, said there had been a 'serious police incident'.
UPDATE: South Yorkshire Police has now confirmed it has undertaken a series of raids in the road today and arrested five people: Read the update HERE