The emergency services, including armed police, have blocked off a Sheffield street this afternoon after concerns were raised for the welfare of a man believed to be on the roof of one of the properties.
The incident in Upwell Street, Brightside is believed to have started at around 4pm this afternoon.
A police negotiator is reportedly trying to talk the man down from the roof of one of the properties.
The fire service, ambulance service and armed police officers and negotiator, are all on the scene.
Florin Flavius Luca says he arrived home earlier this afternoon to find the man on his roof, and armed police in his back garden.
He said: "I've just come back from my first aid course, at around pm and I saw this guy on the top of my roof.
"Police was already here."
Commenting on Twitter, a spokesman for First South Yorkshire said buses were being diverted, as a result of the incident.
They said: "38/38A: Incident on Upwell St, services both directions diverted via Carlisle st, Petre Street, Botham St & Grimesthorpe rd to Upwell St^HY"