By the third week of January, the Peruvian high command had deployed to the Cenepa area what it considered to be enough troops to clear any and all Ecuadorian troops on the Eastern side of the Cordillera del Cóndor. In retrospect, it is likely that Lima was expecting a repetition of the 1981 incident, unaware of the scale of the Ecuadorian deployment. Thus, as a preliminary to the attack, on 21 January Peruvian helicopters began a series of reconnaissance and troop insertion flights on the rear of the Ecuadorian positions, which continued for the next two days. The next day, 22 January, the Ecuadorians detected around twenty Peruvian troops setting up a heliport to the north and rear of the Ecuadorian forward outposts.