  Active galactic nuclei are supermassive black holes surrounded by an
accretion disk, two populations of clouds, bipolar jets, and a dusty torus. The
clouds move in Keplerian orbits at high velocities. In particular, the
broad-line region (BLR) clouds have velocities ranging from $1000$ to $10000$
km s$^{-1}$. Given the extreme proximity of these clouds to the supermassive
black hole, frequent collisions with the accretion disk should occur. The
impact of BLR clouds onto the accretion disk can produce strong shock waves
where particles might be accelerated. The goal of this work is to investigate
the production of relativistic particles, and the associated non-thermal
radiation in these events. In particular, we apply the model we develop to the
Seyfert galaxy NGC 1068. We analyze the efficiency of diffusive shock
acceleration in the shock of colliding clouds of the BLR with the accretion
disk. We calculate the spectral energy distribution of photons generated by the
relativistic particles and estimate the number of simultaneous impacts needed
to explain the gamma radiation observed by the Fermi satellite in Seyfert
galaxies. We find that is possible to understand the measured gamma emission in
terms of the interaction of clouds with the disk if the hard X-ray emission of
the source is at least obscured between $20\%$ and $40\%$. The total number of
clouds contained in the BLR region might be between $3\times10^{8}$ and
$6\times10^{8}$, which are values in good agreement with the observational
evidence. The maximum energy achieved by the protons ($\sim$ PeV) in this
context allows the production of neutrinos in the observing range of IceCube.
