Firefighters are tackling a blaze at a multi-storey car park at the Echo Arena on Liverpool's waterfront.
A total of 12 fire engines are at the building at King's Dock in the city centre.
No-one is believed to have been hurt and it is not yet known how many cars have been damaged.
Crews were first called at 4.42pm and were on scene eight minutes later.
Six fire engines were initially in attendance and crews, wearing breathing apparatus, are tackling the blaze, Mersey Fire and Rescue Service said.
The area was evacuated, including a number of horses taken to safety, as the Liverpool International Horse Show is currently on at the arena venue.
Merseyside Police said "a number" of vehicles are on fire and nearby apartments have been evacuated due to smoke billowing from the blaze.
Police advised members of the public to stay away from the area and traffic restrictions are currently in place.
Mayor of Liverpool Joe Anderson said in a tweet: "Arena Car Park fire have been told everyone safe and no animals hurt seems a land rover went on fire on the 3rd level, horses on 1st the horses have been evacuated to Arena. Will give more news about tonight ASAP."
No-one from the Echo Arena was available for press enquiries.
An evening session of the horse show had been scheduled to take place, starting at 7.30pm.