MEXICO CITY - Actor Sean Penn says he worried that officials were monitoring his trip to interview fugitive drug lord Joaquin "El Chapo" Guzman.

He was right; he just didn't know how closely.

The Mexican newspaper El Universal has published 10 photographs that appear to show Penn and actress Kate Del Castillo arriving at an airport in October and greeting the men who apparently took them to a small airstrip, from which they flew to the jungle camp to meet Guzman.

The photos appear to have been taken with a telephoto lens from long distance. The newspaper said Monday they were part of a Mexican government intelligence file that it obtained.

Figures that closely resemble Penn and Del Castillo are seen wearing dark glasses, and in Penn's case, a baseball cap.

The newspaper says the intelligence file indicates that Mexican agents had been photographing Del Castillo since her first meeting with Guzman's lawyers in the city of Guadalajara, on June 16.