HOSUR, India (Reuters) - At least 10 people received medical treatment, with two hospitalised, after a major fire on Saturday disrupted production at a key Tata Electronics plant in southern India which makes Apple iPhone components.

The incident is the latest to affect Apple's iPhone supply chain just as the company is looking to diversify beyond China and sees India as a key growth market. It is also the latest in a string of incidents to affect Apple suppliers in India over the last few years.

The fire occurred at the plant in the city of Hosur in Tamil Nadu state which makes some iPhone components. It broke out near another building inside the Tata complex which will in coming months turn out complete iPhones.

The fire was contained to one building and has been extinguished fully, top district administrative official K.M. Sarayu said. No decision has been made on when manufacturing can restart, she said.

"Fumes are still coming since it's a chemical hazard. It will take time for the search and rescue team to go inside and do an assessment. We have to wait till tomorrow," she added.

Sarayu said that 523 workers were on shift when the fire broke out in the early morning and that all workers had been evacuated and accounted for.

Savitri, an eyewitness who lives near the plant and only gave her first name, said she heard "loud sounds around 5.30 a.m. (midnight GMT) that sounded like crackers going off. After that we just saw plumes of smoke from the building, and there was thick smoke till at least 10 in the morning."

EMERGENCY PROTOCOLS

Tata Electronics is one of the major contract makers of iPhones in India, along with Foxconn. The company said it was investigating the cause of the fire and would take the necessary steps to safeguard employees and other stakeholders.

"Our emergency protocols at the plant ensured that all employees are safe," a Tata Electronics spokesperson said.

J. Saravanan, a senior district official charged with handling industrial safety, said it was not yet possible to say when production at the facility will resume, as "we will need to go in to understand more, depending on the damage."

He said the injuries were all related to smoke inhalation but give no further detail.

Production was halted and employees sent home for the day following the fire, a person with direct knowledge of the incident said earlier, describing the blaze as chemical-related.

A second industry source said it was not yet clear if a neighbouring building where smartphone manufacturing was due to start by year-end had also been affected.

With the facility inaccessible at the moment, the source said, an assessment of damage from the fire will have to be done later.

Apple made no immediate comment on the incident.

The fire began in an area used to store chemicals, a fire official said on condition of anonymity as he was not authorised to speak to the media.

Last year, Apple supplier Foxlink halted production at its assembly facility in the southern Indian state of Andhra Pradesh after a massive fire led part of the building to collapse.

(Additional reporting by Krishn Kaushik, Aditya Kalra and Munsif Vengattil; Editing by Clarence Fernandez and David Holmes)