  The sources of the astrophysical flux of high-energy neutrinos detected by
IceCube are still largely unknown, but searches for temporal and spatial
correlation between neutrinos and electromagnetic radiation are a promising
approach in this endeavor. All major imaging atmospheric Cherenkov telescopes
(IACTs) - FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up
program of target-of-opportunity observations of neutrino alerts issued by
IceCube. These programs use several complementary neutrino alert streams. A
publicly distributed alert stream is formed by individual high-energy neutrino
candidate events of potentially astrophysical origin, such as IceCube-170922A
(which could be linked to the flaring blazar TXS\,0506+056). A privately
distributed alert stream is formed by clusters of neutrino events in time and
space around either pre-selected gamma-ray sources or anywhere in the sky.
Here, we present joint searches for multi-wavelength emission associated with a
set of IceCube alerts, both private and public, received through mid-January
2021. We will give an overview of the programs of the participating IACTs. We
will showcase the various follow-up and data analysis strategies employed in
response to the different alert types and various possible counterpart
scenarios. Finally, we will present results from a combined analysis of the VHE
gamma-ray observations obtained across all involved instruments, as well as
relevant multi-wavelength data.

High Energy Astrophysical Phenomena