A blaze has left the distinctive domed roof of the historic National Museum Cardiff damaged.
Multiple crews were sent to the museum in Cathays just after 12:00 BST, South Wales Fire and Rescue Service said.
The museum said there had been a small fire in the building's dome, although no staff were hurt and no collections were damaged.
Pictures showed part of the dome had been damaged and several panels being removed by firefighters.
Museum Avenue has been closed and people have been told to avoid the area around the civic centre and Park Place.
"There was a small fire in the dome at National Museum Cardiff on Thursday lunchtime," a museum spokesperson said.
"No staff were hurt and no collections were damaged. The fire has been successfully extinguished and the fire service are now investigating the source of the fire."
What is the National Museum Cardiff?
National Museum Cardiff is part of several sites which make up National Museum Wales.
The museum was founded in 1905 and was established by royal charter in 1907, with the building in Cathays being officially opened in 1927.
The site has collections of archaeology, botany, fine and applied art, geology and zoology.
It attracted more than 530,000 visitors in 2019.