A large explosion has rocked the Indian Point nuclear plant in upstate New York, the facility's management reported.

Entergy Corporation, the company running the plant, said the affected parts of the facility were "safely shut down" and in "safe and stable condition" after a transformer failure on Saturday.

Our @Indian_Point safely shut down after transformer fire outside nuclear side of plant. All emergency systems worked as designed #nuclear — EntergyNuclear (@EntergyNuclear) May 9, 2015

An Entergy spokesman told Reuters news agency that a fire in the transformer had been extinguished and that there was no damage to the reactor.

The fire, which occurred at around 2200 GMT, triggered the closure of the plant's Unit 3 reactor, but the other Unit 2 continues to operate, Jerry Nappi said.

He said there was no information yet as to what caused the transformer failure. The fire was put out by the sprinkler system at the transformer and on-site personnel, Nappi said.

The transformers are located around 90-120 metres away from the reactor.

Indian Point Energy Center is a three-unit nuclear power plant located in Buchanan, New York just south of Peekskill. The plant on the east bank of the Hudson river is located 61km north of New York City.

Residents in the vicinity of the plant reported the explosion and said they saw a 200m-high fireball over the facility.