CH3OH and H2O maser associations at very high angular resolution

6.7 and 12.2 GHz CH_{3}OH (methanol) and 22.2 GHz H_{2}O masers are believed to be good tracers of the earliest phases of high-mass star formation. Interferometric and VLBI (Very Long Baseline Interferometry) observations have shown that water masers are predominantly associated with the innermost portions of the jets/outflows emerging from (proto-)stellar objects. On the other hand, the astrophysical environment traced by the 6.7 GHz (and the associated 12.2 GHz) CH_{3}OH masers is still to be more precisely determined. So far, most high-resolution studies have focused either on CH_{3}OH or on H_{2}O masers and little is known on their connection, wehereas it would be important to study both types of maser emission in the same object. The goal of our long-term project is to perform interferometric and VLBI observations of H_{2}O and CH_3OH masers towards a selected sample of high-mass YSOs where both maser types have been detected. This work presents preliminary results obtained for a few objects of our sample, and discusses possible implications.