At least 60,000 litres (16,000 gallons) of oil has spilled into Rio de Janeiro’s Guanabara Bay and the nearby Estrela river.

The Brazilian oil company Transpetro said the 4km (2.5-mile) spill was caused by thieves who broke into a pipeline last week.

Workers have cleared most of the oil, but a biologist said it would be weeks until the extent of the damage to local wildlife would be known.