  We present the results of a K-band imaging survey of 40 arcmin^{2} in fields
around 14 radio-loud AGN (6 radio galaxies and 8 quasars) with z>1.5. The
survey, 80% complete to K<19.2 and complemented by R-band imaging, aimed at
investigating whether extremely red objects (EROs) are present in excess around
high-z AGN, and to study the environment of z>1.5 radio galaxies and radio-loud
quasars. At $18<K<19$ the differential galaxy counts in our fields suggest a
systematic excess over the general field counts. At K<19.2, we find an excess
of galaxies with R-K>6 compared to the general field. Consistently, we also
find that the R-K colour distribution of all the galaxies in the AGN fields are
significantly redder than the colour distribution of the field galaxies. On the
other hand, the distribution of the R-K colours is undistinguishable from that
of galaxies taken from literature fields around radio-loud quasars at 1<z<2. We
discuss the main implications of our findings and we compare the possible
scenarios which could explain our results.
