Chevron drilling caused Brazil oil spill

Drilling by Chevron off Brazil's coast led to an oil spill near the US company's Frade project, an official with Brazilian energy regulator ANP said on Monday.

Chevron says oil seeps have created a "sheen" with a volume of 400 to 650 barrels of oil on the ocean in the area, which lies 370 kilometers (230 miles) northeast of Río de Janeiro.

President Dilma Rousseff on Friday urged a thorough investigation of the incident, which may increase scrutiny of safety in Brazil's offshore operations as it seeks to tap huge, newly found reserves and become a major oil exporter.

"What was detected is that with the drilling, there was an increase in pressure and there was a crack in the rock which caused the oil to leak to the surface," ANP Director Floriano Carvalho told reporters.

The company has said the causes of the incident are still being investigated.

Carvalho said the leak is continuing and that the ANP had authorized Chevron to cap the well. Chevron had previously said it suspended drilling the well, but that production was continuing. The company maintains that production activities are unrelated to the oil seeps.

Chevron said on Sunday it had up to eight vessels working at the "sheen."

"Chevron Brazil is deploying experts from Chevron Corporation's global response team and continues to inform and work with government agencies and industry partners in response to the matter," the company said in a statement.