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We present multi-epoch Very Long Baseline Array (VLBA) H$_2$O maserobservations toward the massive young stellar objects (YSOs) VLA 2 and VLA 3 inthe star-forming region AFGL 2591. Through these observations, we have extendedthe study of the evolution of the masers towards these objects up to a timespan of $\sim$ 10 yrs, measuring their radial velocities and proper motions.The H$_2$O masers in VLA 3, the most massive YSO in AFGL 2591 ($\sim$30--40~M$_{\odot}$), are grouped within projected distances of $\lesssim$ 40mas ($\lesssim$ 130 AU) from VLA 3. In contrast to other H$_2$O masers in AFGL2591, the masers associated with VLA 3 are significantly blueshifted (up to$\sim$ 30 km s$^{-1}$) with respect to the velocity of the ambient molecularcloud. We find that the H$_2$O maser cluster as a whole, has moved westwards ofVLA~3 between the 2001 and 2009 observations, with a proper motion of $\sim$1.2 mas yr$^{-1}$ ($\sim$ 20 km s$^{-1}$). We conclude that these masers aretracing blueshifted outflowing material, shock excited at the inner parts of acavity seen previously in ammonia molecular lines and infrared images, andproposed to be evacuated by the outflow associated with the massive VLA 3source. The masers in the region of VLA 2 are located at projected distances of$\sim$ 0.7$''$ ($\sim$ 2300 AU) north from this source, with their kinematicssuggesting that they are excited by a YSO other than VLA 2. This driving sourcehas not yet been identified.

Multi-epoch VLBA H$_2$O maser observations toward the massive YSOs AFGL 2591 VLA 2 and VLA 3