(Reuters) - A unit at Indian Point nuclear plant in Buchanan, New York state, was shut down following a transformer failure and fire on Saturday, and at one point smoke was seen rising from the plant.

But the plant was stable and there was no danger to the public or employees, Entergy Corp, the company that operates the facility, said.

Several people tweeted from nearby that they saw a big explosion.

Several emergency calls reported a loud noise at the plant, which is located about 40 miles (65 km) north of New York City on the east bank of the Hudson River, a New York State police spokesman said.

Unit 3 at the plant was shut down following the transformer failure, Entergy said in a message on Twitter.

"No threat to public safety at any time," the company said on Twitter.

The police spokesman said no injuries were reported at the site.

CNN reported that a spokesman at Indian Point Facilities said a transformer on the non-nuclear side of the plant failed and caused the fire.

Sprinklers put out the fire and the reactor shut down automatically, CNN said.

The plant has two units, Unit 2 and Unit 3.

On Friday, Entergy returned the 1,031-megawatt Unit 3 back to service after shutting it down the previous day to repair a steam leak on the non-nuclear side of the plant.

(Reporting by Victoria Cavaliere, Lisa Lambert and Jonathan Oatis, Writing by Alex Dobuzinskis; Editing by Christian Plumb and Frances Kerry)