Mid & West Wales Fire Service told ITV News that firefighters will remain at the National Library of Wales throughout the day, as investigations continue into the fire that damaged the building's roof on Friday.
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Western Power Distribution say around 500 homes are without power due to damage caused by Storm Brian.
Helping young people 'earn, learn or serve' is among the policies Plaid Cymru will focus on ahead of the next election.
Trains have been cancelled and roads closed across Wales today after Storm Brian has been causing disruption.