The ministry said in a statement late Wednesday that the operation was aimed at “isolating the narcoterrorists,” referring to the Shining Path, a guerrilla movement that was largely dismantled more than a decade ago.
The ministry said the armed forces and the national police had established a joint command but that “reserve and discretion is required in a case of this delicate nature.”
The government had earlier declared a state of emergency in the Echarate district of the southeast Cusco region, where the workers were being held.
The workers include 28 people employed by the Swedish company Skanska and eight from Construcciones Modulares, according to the Swedish firm.
Peruvian news reports have said the kidnappers are seeking a $10 million ransom.
The workers were reportedly approached by an armed group that handed out leaflets and forced them to chant slogans, said Raul Donayre, an official from Transportadora de Gas del Peru, a contractor for the two companies.
The leftist Shining Path was largely dismantled when its leaders were captured in the mid-1990s, but not before a conflict that left some 70,000 people dead, according to Peru’s Truth and Reconciliation Commission.
However, remnants of the guerrilla group still operate in remote regions of the country.