Suspected Shining Path rebels abducted 30 Peruvian employees of the Swedish construction company Skanska on Monday at a natural gas plant in the Amazon jungle and later released all but seven, police said.
The insurgents raided the Skanska camp in the Camisea natural gas field in Kepashiato before dawn, breaking down doors and robbing workers before taking away the hostages, the Interior Ministry said in a statement.
Skanska spokesman Edvard Lind in Sweden said all the abducted employees were Peruvians. He said he did know whether the kidnappers were rebels or whether they were seeking ransom.
The workers were building a new gas treatment plant on which work began last year, said Lind.
The cocaine-trade funded Shining Path is today only a small remnant of the fanatical Maoist group that terrorized Peru in the 1980s-1990s before its leader, Abimael Guzman, was captured.
It is believed to only number about 300 to 500 fighters but represents a growing threat, not just in the Ene and Apurimac Valley region where more than half of Peru's coca crop grows, but also in adjacent regions such as that where Monday's kidnapping occurred.
Since 2008, more than 50 Peruvian troops have been killed in Shining Path attacks.
The insurgency has not committed a mass abduction since 2003, when it seized 60 workers of the Argentine company Techint working on a Camisea pipeline.
They were freed two days later, and officials said no ransom was paid.