RIO DE JANEIRO (Reuters) - Armed men shot at members of a convoy transporting uranium to one of Brazil’s two working nuclear power plants on a coastal road in Rio de Janeiro state on Tuesday, police and the company managing the plant said.

They said the truck carrying the nuclear fuel and its police escort came under attack when it was passing by the town of Frade, about 30 km (19 miles) from Angra dos Reis, where the reactor is located.

Policemen guarding the convoy returned the attackers’ fire, police said. They said there were no injuries or arrests and the armed men fled.

Eletronuclear, the Centrais Elétricas Brasileiras SA subsidiary that manages the Angra nuclear plants, said in a statement that the uranium being transported was not dangerous and that the shipment was not delayed by the attack.

It said the incident occurred when police escorting the truck fanned out alongside the road as a precautionary measure after hearing nearby gunshots. The armed men then started firing on some of the heavily armed “shock battalion” accompanying the shipment, Eletronuclear said.

The nuclear fuel used in the two reactors in Brazil, Angra 1 and Angra 2, is produced in a government installation in Resende, a city in the interior of Rio de Janeiro state located 130 km (80.78 miles) from Angra dos Reis.

Brazil only processes uranium to be used as fuel for power plants, under the supervision of the International Atomic Energy Agency.