  We present observations of continuum and molecular lines towards the
protostar candidates IRAS 21307+5049 and IRAS 22172+5549. Single-dish maps in
the 12CO(2--1), C18O(2--1), HCO+(1--0) lines and sub-mm continuum are compared
with interferometric maps in the 12CO(1--0) line and 3 mm continuum, and with
mid- and near-infrared images. A plausible interpretation of our data based on
the continuum maps and spectral energy distributions is that two components are
present: a compact molecular core, responsible for the continuum emission at
wavelengths longer than ~25 \mum, and a cluster of stars located close to the
center of the core, but not spatially coincident with it, responsible for the
emission at shorter wavelengths. The core is approximately located at the
center of the associated molecular outflow, detected for both sources in the
12CO(1--0) and (2--1) lines. The cores have masses of ~50 M_{\odot}, and
luminosities of ~10^{3} L_{\odot}. The outflows parameters are consistent with
those typically found in high-mass young stellar objects. Our results support
the hypothesis that in these sources the luminosity is dominated by accretion
rather than by nuclear burning. We conclude that the sources embedded inside
the cores are likely protostars with mass ~5-8 M_{\odot}.
