Residents have been asked to remain indoors after roof tiles were thrown in Grand Parade, Brighton, where a man is on a roof, police said.
Police were called to a report of a man on a roof at the junction with Kingswood Street just before midnight on Thursday (30 August).
A spokesman said: “When officers arrived roof tiles were thrown down and it was necessary to cordon off the immediate area to protect the public.
“Two police cars have been damaged by tiles and other objects thrown from the roof.
“Nobody has been injured.”
The southbound carriageway of the A23 in Grand Parade is currently closed between Richmond Parade and Edward Street and traffic is being diverted away from the area.
Circus Street at the back of the building is also closed to traffic.
Northbound traffic is not affected.
Police negotiators have been working throughout the night to get the man to come down, the spokesman said.
“Residents in the flats between Kingswood Street and Morley Street on Grand Parade are being requested to remain indoors away from the windows until the situation is resolved,” said the spokesman.
“We appreciate everybody’s patience while we work to resolve this situation peacefully and without injury to anyone.”