  Cosmic neutrino events detected by the IceCube Neutrino Observatory with
energy $\gtrsim 30$ TeV have poor angular resolutions to reveal their origin.
Ultrahigh-energy cosmic rays (UHECRs), with better angular resolutions at $>60$
EeV energies, can be used to check if the same astrophysical sources are
responsible for producing both neutrinos and UHECRs. We test this hypothesis,
with statistical methods which emphasize invariant quantities, by using data
from the Pierre Auger Observatory, Telescope Array and past cosmic-ray
experiments. We find that the arrival directions of the cosmic neutrinos are
correlated with $\ge 100$ EeV UHECR arrival directions at confidence level
$\approx 93\%$. The strength of the correlation decreases with decreasing UHECR
energy and no correlation exists at energy $\sim 60$ EeV. A search in
astrophysical databases within $3^\circ$ of the arrival directions of UHECRs
with energy $\ge 100$ EeV, that are correlated with the IceCube cosmic
neutrinos, resulted in 18 sources from the Swift-BAT X-ray catalog with
redshift $z\le 0.06$. We also found 3 objects in the K\"uhr catalog of radio
sources using the same criteria. The sources are dominantly Seyfert galaxies
with Cygnus A being the most prominent member. We calculate the required
neutrino and UHECR fluxes to produce the observed correlated events, and
estimate the corresponding neutrino luminosity (25 TeV-2.2 PeV) and cosmic-ray
luminosity (500 TeV-180 EeV), assuming the sources are the ones we found in the
Swift-BAT and K\"uhr catalogs. We compare these luminosities with the X-ray
luminosity of the corresponding sources and discuss possibilities of
accelerating protons to $\gtrsim 100$ EeV and produce neutrinos in these
sources.
