By Agence France-Presse
"We could face an environmental catastrophe," Beatriz Alva, a manager with state oil firm Petroperu, told channel N television.
Alva gave the volume of spilled crude as "more or less 8,000 barrels."
Residents in a remote community of Morona district, in the northeastern Loreto region, "cut the pipeline" on Tuesday night and prevented workers from repairing it, Alva said.
Residents of the district are overwhelmingly indigenous people.
Villagers had threatened last week to cut the pipeline, which moves crude from Amazonian wells to coastal refineries, in a protest against alleged irregularities in local elections held in October.
Peru's Amazon region has seen repeated oil spills in recent years, some the results of a lack of maintenance. Others were caused by protest attacks.
The country produced 127,000 barrels of oil per day in 2017, according to the BP Statistical Review of World Energy.