Abstract
A three-dimensional Monte-Carlo simulation of EAS initiated by primary proton and primary gamma quanta is carried out, observation level 700 g cm-2, on the basis of a new phenomenological interaction model. The results obtained confirm the criteria adopted in the Tien-Shan experiment for the selection of EAS initiated by primary gamma with ultra-high energies. The lateral distribution of electrons and electron energy flux are steeper for showers initiated by primary gamma quanta than for EAS generated by primary protons. The shape of the lateral distribution of muons with Emu >5 GeV in gamma-initiated EAS does not essentially differ from the corresponding characteristics in normal showers.