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We have obtained HST WFPC2 and ground-based images of two low surfacebrightness dwarf spheroidal galaxies in the M81 group, FM1 and KKH57. Theircolour-magnitude diagrams show red giant branches with tips at I = 23.77 +-0.14 and I = 23.97 +- 0.17, respectively. The derived true distance moduli,27.66 +- 0.16 and 27.96 +- 0.19, agree well with the mean distance modulus ofthe M81 group, 27.84 +- 0.05. Absolute V magnitudes of the galaxies (-11.46 and-10.85), their colours ((B-V) = 0.88 and 0.80), and central surfacebrightnesses ($\Sigma_{0,V}$ = 24.8 and 24.4 mag/$\sq\arcsec$) are in the rangeof other dSph companions of M81, M31, and Milky Way. With two new objects themaximum projected radius of the dwarf spheroidal subsystem around M81 is 380kpc.Comment: 16 pages, 8 figures, accepted for publication in A&

WFPC2 observations of two dwarf spheroidal galaxies in the M 81 group