COPENHAGEN, June 13 (Reuters) -

Boliden said on Tuesday it had halted production at its Ronnskar copper smelter in Sweden after a fire broke out late on Monday at facility, its biggest production unit.

The Swedish group said in a statement there were no reports of persons injured in the fire.

"All production at Ronnskar is stopped until further notice, an initial assessment is that this can be resumed within a few weeks," it said. "It is currently not possible to assess the extent of the damage that has occurred, but the cell house has burned down."

(Reporting by Louise Breusch Rasmussen, editing by Terje Solsvik and Anna Ringstrom)