The catalytic reduction of NO by CH4 over Co/ZSM-5 zeolite is studied by means of transient in situ DRIFT, SSITK and TAP analyses. Co ions located at the interface of Co clusters and zeolite are found to react with NO in the presence of oxygen to form anchored NO2delta+ species stabilized under reaction conditions. These species form the main active sites for activating methane molecule. Two ways of CO2 formation from the same intermediate including fragments of both NO2 and partially dehydrogenated CH4 molecule are proposed in the mechanistic scheme of the reaction.