PUNE, India (AP) — A fire broke out Thursday at a building under construction at Serum Institute of India, the world’s largest vaccine manufacturer, but production of COVID-19 vaccine will not be affected, the company said.

Firefighters were extinguishing the flames, the fire office in Pune city in southern Maharashtra state said. The cause of the fire and extent of damage were not immediately clear.

“We have rescued three people and there are no casualties,” said fire official Prashant Ranpise, who was supervising rescue operations.

The company said the fire was restricted to a new facility it is constructing to increase production of COVID-19 vaccines and ensure it is better prepared for future pandemics.

It said the fire did not affect existing facilities making COVID-19 vaccines or a stockpile of around 50 million doses.

CEO Adar Poonwala said there would be no loss in vaccine manufacturing because the company has other available facilities.

“So far the most important thing is that there have been no lives lost or major injuries due to the fire, despite a few floors being destroyed,” Poonawalla said.

Images showed huge plumes of smoke billowing from the building as firefighters worked to extinguish the blaze. Dozens of company workers in lab suits left the compound.

Serum Institute of India is the world’s largest maker of vaccines and has been contracted to manufacture a billion doses of the AstraZeneca/Oxford University vaccine.

Poonawalla said in an interview with The Associated Press last month that it hopes to increase production capacity from 1.5 billion doses to 2.5 billion doses per year by the end of 2021. The new facility is part of the expansion.

Of the more than 12 billion coronavirus vaccine doses expected to be produced this year, rich countries have already bought about 9 billion, and many have options to buy even more. As a result, Serum Institute is likely to make most of the vaccines that will be used by developing nations.