A man climbed to the top of the historic York Minster cathedral overnight.
Officers said they were dealing with the 'ongoing incident' after the unidentified male went up the top of scaffolding shortly after 11pm on Tuesday.
An image on social media appeared to show a huge emergency services response in the area.
Fortunately the man climbed down 'on his own accord' in the early hours of Wednesday morning, leaving the scene in the care of paramedics and police.
North Yorkshire Police said of the incident: "Please avoid the area around the Minster in York while we deal with an ongoing incident.
"A man is currently on top of the Minster having climbed the scaffolding all the way to the top shortly after 11pm (on 23 November).
"The priority for us and the other emergency services at the scene is to bring this incident to a safe conclusion.
"We don't believe there is a threat to wider public safety, however we do ask people to avoid the area to allow us to do our job.
"Thank you for your co-operation."
However, a North Yorkshire Fire & Rescue Service spokesperson later told YorkMix: “Crews liaised with police and ambulance crews to establish a rescue plan.
“The male climbed down the scaffolding via the internal ladder of his own accord and was left in the care of police and ambulance crews.”
One person posted an image on social media of the scene, appearing to show a line of fire pumps.
They said: "Emergency services including North Yorkshire Police and North Yorkshire Fire and Rescue Service at York Minster dealing with an incident.
"There's no wider threat to Minster or public. Give them space to bring it to a peaceful and safe conclusion."
Police have been contacted for further information.
The iconic York Minster cathedral was built over 200 years from 1220 and is a major tourist attraction as well as a place of worship.
