We propose that TeV-PeV neutrinos, recently detected by the IceCube, can be produced by neutrons interacting with the matter of the accretion disks around black holes in active galaxies. Neutrons are extracted from nuclei which are disintegrated in jets of active galaxies. The neutrino spectra, expected from the whole population of the active galaxies, are confronted with the observations. We propose that neutrinos produced in such scenario can explain the extra-galactic neutrino background recently measured by the IceCube neutrino
detector, provided that 5% fraction of galaxies is AGN and a few percent of neutrons reach the accretion disk.