The first blaze was called in at 9.17am at Brunswick Road in Burngreave.
The second was called in at 9.43am at Crabtree Court in Fir Vale.
Four appliances and an aerial ladder are currently at the Burnswick Road fire while three appliances are at the Crabtreet Court incident.
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Both fires were described as ‘still ongoing’. No details are currently available on any casualties in either fire.
More to follow.