GRP caught Pradeep Kumar when he was moving suspiciously and about to board the Delhi-bound Sampark Kranti Express arrival here by the Dimapur-Guwahati BG Express.
Two pistols and 90 rounds of cartridges were recovered from his possession during search, GRP sources said.
Kumar claimed that he was a constable of the Nagaland Police. The veracity of his statement was being checked.